Find height by a corresponding shadow (Intro Geometry #15)

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  • Опубліковано 31 січ 2025

КОМЕНТАРІ • 82

  • @JoAnnsSchool
    @JoAnnsSchool  4 роки тому +3

    G.E.D. Math 6f, Solving Proportions (cross cancelling)
    ua-cam.com/video/T9EacEHGJUA/v-deo.html
    Grade 6 Math #5.3, Proportions - proportional fractions
    ua-cam.com/video/AbngXD7j9cg/v-deo.html
    Grade 6 Math 5.4A, Solve Proportions by Equivalent Ratios (New Version)
    ua-cam.com/video/lwrAIyES4GA/v-deo.html

  • @Tahya1970
    @Tahya1970 7 місяців тому +2

    You could use a shadow length of a known object like a ruler or yardstick. Then, find the ratio of the known info and compared the shadow length of the flower.

  • @w.nick.w5619
    @w.nick.w5619 5 років тому +22

    Thank you it really helped me thanks ( I cant belive I am seeing this in 2020 and made in 2015)

    • @JoAnnsSchool
      @JoAnnsSchool  5 років тому +6

      Mathematics is timeless. Believe it or not I learned how to multiply fractions in the 1960s. I'm a grandmother. They still teach the same basic way. Algebra doesn't change. Geometry doesn't change. I'm so glad I could help you!

    • @nikki6252
      @nikki6252 4 роки тому

      Me rn😭

    • @fizzah_syed
      @fizzah_syed 3 роки тому +1

      I’m watching in 2021 because I have a test with this question

    • @Jon_Is_Better
      @Jon_Is_Better 11 місяців тому

      2024

  • @iwillfeedtheplatypus3623
    @iwillfeedtheplatypus3623 4 роки тому +7

    this video helped me a lot and made it easier for me to calculate the measurements. Thank you A lot :) glad that this video was posted, it still relates from then and now. Thank you :)

  • @etsukei
    @etsukei 3 роки тому +2

    thank u i didn't play attention in class today and this 3 minute video saved me from failing my test

  • @loriraye9081
    @loriraye9081 5 років тому +4

    Thank you so much!! I've been having all sorts of problems with these questions and now it makes so much sense xx

  • @Nexus-Co
    @Nexus-Co 4 роки тому +1

    4year old video just saved me from my test thank you so much

    • @JoAnnsSchool
      @JoAnnsSchool  4 роки тому

      Math is timeless. Glad it helped! :-)

  • @KreyolGaming
    @KreyolGaming 4 роки тому +4

    I'm on here for the asvab because I found this 2 times but the second time I was close and stop I didn't do it thnx so much

    • @JoAnnsSchool
      @JoAnnsSchool  4 роки тому

      Try watching this short playlist and you'll be a pro at it. :-) Grade 8 Math, Chapter 12, Pythagorean Theorem Playlist
      ua-cam.com/play/PLKi4WTp6PRGWAOm9mgM05yKrUreEcd0gg.html

  • @mw7755
    @mw7755 5 років тому +4

    this was legit so freaking good what the heck

  • @jrdnkwc1709
    @jrdnkwc1709 4 роки тому +3

    This just helped me in my similar figures and triangles assignment. Thank you so much 😊

  • @zawmbikilaa
    @zawmbikilaa 3 роки тому +1

    yo its that easy? tysm for this video now i can make my math assignments:)

  • @cast5439
    @cast5439 Рік тому

    studying for an algebra test this is helping me a lot thanks.

    • @JoAnnsSchool
      @JoAnnsSchool  Рік тому

      Best of luck! You can also scroll these playlists for topics of your test. :-)
      Algebra I Course Playlist:
      ua-cam.com/play/PLKi4WTp6PRGXzkjUUMYVChM2WxWfgIrK4.html
      Algebra 2 Playlist Chapter 1 thru 15
      ua-cam.com/play/PLKi4WTp6PRGVGCVa4jrZLB7zFNG3mRg0N.html

  • @ahira302
    @ahira302 5 років тому

    Thank you Very much mam. You have given me alot of trignomatry. I strongly respect you as Indian चेला।

  • @Vertican
    @Vertican 3 роки тому +1

    thanks this helped me on my homework lol

  • @doliver4884
    @doliver4884 4 роки тому

    I got a shadow problem correct on my midterm exam because of your video. Thank you so much.

  • @peytonbarrow8195
    @peytonbarrow8195 11 місяців тому

    Thank you so much!! This video helped me understand a lot more!

  • @informationtv8565
    @informationtv8565 3 роки тому +1

    Nice video very helpful for me

  • @ankits_world
    @ankits_world 4 роки тому +1

    Thanks dear!💖

  • @ShaunPaget
    @ShaunPaget 4 місяці тому +1

    simplify. 18 0ver 30 = x over 56. no need for the extra steps in trig.

  • @hectorzeroni1088
    @hectorzeroni1088 Рік тому

    Wonderful video!Thank you so much

  • @subatomicparticle
    @subatomicparticle 4 роки тому

    I tried to do this in a different way and got the same answer. I used a calculator though I just figured out that 18 is 60% of 30. So I did 56×60% which is equal to 33.6. somehow I feel like this is more common sense. The way you did it feels like more steps to remember.

    • @JoAnnsSchool
      @JoAnnsSchool  4 роки тому

      It's just the Pythagorean theorem , a² + b² = c².

  • @umidzakirov6759
    @umidzakirov6759 4 роки тому

    Thank you! it helped me to understand how it works.

  • @Liizziee
    @Liizziee 7 років тому +2

    Could you explain how to do one of the problems on page 389 in the discovering geometry book? Im just not quite sure on how to calculate them

    • @Liizziee
      @Liizziee 7 років тому +1

      Or anything similar to that it would be a great help because you teach so well

    • @JoAnnsSchool
      @JoAnnsSchool  7 років тому +1

      ButterIsMyLife , I don't have that particular book but I am on Facebook as JoAnn's School and you can take a picture of the problem and send it to me through the messaging system. I'll see what I can do.
      Otherwise if there's any way that you can type the problem into this comment I'll try to solve it but I think taking a picture would be easier if you can.

  • @chouthmalsinghania7808
    @chouthmalsinghania7808 4 роки тому +1

    Could you please explain why angle B=angle e ???

    • @JoAnnsSchool
      @JoAnnsSchool  4 роки тому

      Hmmm, I should have clarified that the five dots were the "given" information. Sorry about the confusion. It told us that c = f, b = e, h and side df (the 18 ft)correspond, a = d, bc as 55 ft and ef as 30 ft correspond. Watch these and it should make your life easier:
      Grade 8 Math #11.3a, Discovering Angle-Angle (AA) similarity
      ua-cam.com/video/BbT_TYS8rFA/v-deo.html
      Grade 8 Math #11.3b, Using the Angle-Angle (AA) Similarity Postulate
      ua-cam.com/video/iVca2aznoR8/v-deo.html
      Grade 8 Math #11.3c, Finding missing measures in Similar Triangles
      ua-cam.com/video/eJDJXHZZN6I/v-deo.html
      High School Geometry 8.1, Similarity in Right Triangles
      ua-cam.com/video/hz1RePt7kGE/v-deo.html

  • @kirbyishappy
    @kirbyishappy 4 роки тому

    It was really useful, thanks!

  • @57cactus1
    @57cactus1 2 роки тому

    Isn't it possible to calculate the height of a tall tree in isolation, without doing a comparison with something else? If you know the length of its shadow, you know the angle of the shadow on flat ground, and you know the tree stands perpendicular to the flat ground, then with pencil, paper, ruler, and protractor draw the triangle. If the shadow length is, say, 40 feet, then on paper draw a length of 40 centimeters. Then see how many centimeters the height of the triangle is and convert to feet.

    • @JoAnnsSchool
      @JoAnnsSchool  2 роки тому

      Shove a stick, fence pole, something into the ground near it. Measure the height and length of the stick and its shadow. Then use those lengths to find the height of the tree. Just comparing the shadow length to the tree won't give you the trees height because you wont know the proportion or ratio to use. By using a stick near it, you can compare the sticks shadow to the trees shadow to know the proportional difference.

  • @arushvandara8270
    @arushvandara8270 3 роки тому

    1:59 i know I am supposed to be paying attention to the problem but what is that mark on her hand

    • @JoAnnsSchool
      @JoAnnsSchool  3 роки тому

      I'm a grandma. I'm old. That's called an "age spot". I have many. Age spots are a result of the body producing excess melanin, more likely to those over 40. Melanin is the pigment that gives skin its color. Since making this lesson, my hand has 2 more. (sigh) Growing older isn't fun after a certain age. :-(

  • @PaloSoldierofAllah
    @PaloSoldierofAllah 6 років тому +1

    Than you so much
    So kind of you 🌹🌹🌹

  • @reinasatorre7433
    @reinasatorre7433 5 років тому +1

    amaaaaaaaaaazing
    thanks

  • @Ace.xfitnes
    @Ace.xfitnes 4 роки тому

    Thanks

  • @aidend0
    @aidend0 2 роки тому

    i have my final math exam tomorrow, thanks so much

  • @abdusalomabdukayumov8640
    @abdusalomabdukayumov8640 2 роки тому

    Thank you

  • @marianak3125
    @marianak3125 5 років тому

    How do you know that the other two angles of the triangles are equal? I understand that the angle from the tree to the ground is 90 degrees.

    • @JoAnnsSchool
      @JoAnnsSchool  5 років тому +2

      Sorry about the previous comment, I deleted it. I thought you said the sides. All triangles have 180 degrees inside. If one angle is a right angle of 90 degrees, and the length of the line segments that make the 90 degree angle have the same length, then the other two angles must be equal to each other. If one of the side lengths, or legs, is longer than the other then the angles will be different from each other because the longer leg will make a smaller angle where it meets the hypotenuse. I hope that makes sense! Let me know!

  • @evilweevil4976
    @evilweevil4976 7 років тому

    i like your videos they help me study :)

  • @brandyfinley4957
    @brandyfinley4957 4 роки тому

    I just had a test with this question, I did it a different way, I saw the larger triangle as a dialation of the smaller triangle, so I took the scale factor between the shadow length s and applied it to the heights, I had easier numbers to work with, did I get it right?

  • @GiveMeNameTech
    @GiveMeNameTech 4 роки тому +1

    Im in Philippines and we have homestudy because of COVID 19 this help me thanks

    • @JoAnnsSchool
      @JoAnnsSchool  4 роки тому

      You're welcome! And just in case you need them, my channel has playlists of grade 1 through grade 8, Algebra 1, Algebra 2, and high school Geometry. Each playlist has over a hundred lessons for the entire school year, in order. :-)

  • @jeilejarzo9176
    @jeilejarzo9176 4 роки тому

    What if the shadows of different tree have different term? Like 45m and 12ft?

    • @jeilejarzo9176
      @jeilejarzo9176 4 роки тому

      Should i use the same formula that you use?

    • @JoAnnsSchool
      @JoAnnsSchool  4 роки тому

      Oh okay. There are two triangles made, one from the chimney and its shadow and another from the gate and its shadow. We're comparing the two triangles. They're in proportion to each other. Can you message me on Facebook so I can send you a drawing of this? facebook.com/JoAnnsSchool/

    • @jeilejarzo9176
      @jeilejarzo9176 4 роки тому

      Oh sure. Actually this is for my nephew's work. I need to teach her because she don't understand it too.

    • @jeilejarzo9176
      @jeilejarzo9176 4 роки тому

      @@JoAnnsSchool message sent

  • @abrahamminds8870
    @abrahamminds8870 4 роки тому +1

    Wat of d shadow of a translucent material.

    • @JoAnnsSchool
      @JoAnnsSchool  4 роки тому

      A shadow is a shadow.

    • @abrahamminds8870
      @abrahamminds8870 4 роки тому

      Cause my teacher said shadows are casted perpendicular to the object

    • @JoAnnsSchool
      @JoAnnsSchool  4 роки тому

      Perpendicular means "making a 90° angle, or a right angle", just like the tree is making a right angle with the ground. :-)

    • @abrahamminds8870
      @abrahamminds8870 4 роки тому

      @@JoAnnsSchool pls can I send a question to you

    • @JoAnnsSchool
      @JoAnnsSchool  4 роки тому

      Anyone can message me on my JoAnn's School Facebook page at facebook.com/JoAnnsSchool/

  • @arnoudvdm8867
    @arnoudvdm8867 5 років тому +1

    Why are e and b equale?

    • @JoAnnsSchool
      @JoAnnsSchool  5 років тому

      Angle e and angle b are angles with the same degree measure. Watch this video starting at 2:39: Degrees of an Angle, Circle
      ua-cam.com/video/ws37b-7UrJk/v-deo.html

    • @arnoudvdm8867
      @arnoudvdm8867 5 років тому

      Ooow thank you😀

    • @arnoudvdm8867
      @arnoudvdm8867 5 років тому

      It's cause of the sun is making the shadows the same anquele

    • @arnoudvdm8867
      @arnoudvdm8867 5 років тому

      Sorry for bad English

  • @1XX1
    @1XX1 4 роки тому

    If a skyscraper casts a shadow
    And directly UNder the skyscraper farm Princess has a laundry line. Arent EACH EQUIVALENT
    to each other? Then why not use each as counterweights.

  • @JamieChurchlakotawannabe
    @JamieChurchlakotawannabe 4 роки тому

    Um how does 56 get turned into 55???

  • @rameshpandey8162
    @rameshpandey8162 3 роки тому

    Nice

  • @watchingfromtheshadows1338
    @watchingfromtheshadows1338 4 роки тому

    The shadow knows.

  • @ankits_world
    @ankits_world 4 роки тому +1

    Its trigonometry

  • @ryanaguon33
    @ryanaguon33 10 місяців тому +1

    instead of GPS, should've used the shadow of the helicopter to pinpoint target.

  • @jesusmayers1320
    @jesusmayers1320 6 років тому

    Thk

  • @dorothyrobertson8118
    @dorothyrobertson8118 7 років тому +3

    Why 55?
    Should that be 56?

    • @JoAnnsSchool
      @JoAnnsSchool  7 років тому +1

      Dorothy Robertson, I chose 55 ft as the shadow length of the taller tree so the height of the taller tree would equal a whole number. If the shadow was 56 ft, then our proportion would be h/18' = 56/30. Then we'd have 18 (56) = 1,008. Then h = 1,008 divided by 30 = 33 3/5 ft.
      I made the shadow 55ft so we wouldn't have to deal with that fractional measure.

  • @Vizztory
    @Vizztory Місяць тому

    ???