How to draw the external tangents to two unequal circles

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  • Опубліковано 4 січ 2025

КОМЕНТАРІ • 38

  • @gusgarrison9211
    @gusgarrison9211 Рік тому +7

    Thank you so much. With these simple definitions, I can calculate these lines for collision purposes in a game

  • @Z-eng0
    @Z-eng0 12 годин тому

    Guys, I finally understood the method, anyone wondering how the Euclidean axioms/postulates apply to this I'll write it in a reply to this comment.
    I'll say this in advance though, I'll only write the details involving the 2 circles tangent (and maybe the circle & external point tangent) and assume some other stuff was proved (I already proved the rest by hand so maybe I'll write a comment in this man's respective video), stuff like: perpendicular bisector of a line, perpendicular of a line at an external point, and parallel of a line at an external point (feel free to ask if you're unable to find a concrete proof) that's it for the intro

    • @Z-eng0
      @Z-eng0 12 годин тому

      So basically I prove it by going the reverse way, assuming the thing was drawn then going backwards, of course even I won't go as far as to develop a method from scratch which is why I came here 😅.
      Draw sth that looks like the desired tangent, draw the radii of the 2 circles R1 and R2 (R1 > R2), also connect their centers (M and N respectively).
      Assume the tangent drawn is PQ, where P is on circle M with R1 and Q is on circle N with R2.
      Since MP and NQ are both perpendicular on PQ, therefore they're both parallel to each other.
      Draw EN such that EN is parallel to PQ.
      We notice that m

    • @Z-eng0
      @Z-eng0 12 годин тому

      Now I'll state the steps again.
      We construct a radius of circle M at A, and one of circle N at B, where MA = R1, NB = R2, and R1 > R2.
      We open the compass with distance NB = R2, place it on A, and mark an intersection with MA at C, AC = R2 making MC = R1 - R2.
      We construct circle dr centered at M with radius MC (R1 - R2).
      Draw a tangent from circle dr to point N.
      To do so first connect MN, bisect it at O, draw circle O with radius OM (or ON same distance really) not its intersection with circle dr at E and E' (where E is the upper point), then finally draw EN.
      EN is the tangent we're looking for, just not at the right spot.
      Connect ray ME (and maybe ME' if we want the lower tangent) to intersect circle M at P.
      Now we take our tangent EN and make a parallel to it at point P, and that's it, it should intersect circle N at Q

    • @Z-eng0
      @Z-eng0 12 годин тому

      I know I wrote hell of a lot, but explaining in text is not really my forte 😅, I struggle a lot with it

  • @jackmclellan1884
    @jackmclellan1884 Місяць тому +1

    Thanks for this! I'm a CAD engineer and I used this technique to join 2 curving roads to each other perfectly

  • @MichaelChin1994
    @MichaelChin1994 Рік тому +1

    Thank you so much! I've been banging my head against a wall for 3 days trying to figure this out on my own.
    Got kinda close, actually. But man, I'm not sure I ever would have resolved it, though. Thank you!

  • @kebedek7879
    @kebedek7879 3 роки тому +10

    God bless you! Keep working

  • @michaelkyte7252
    @michaelkyte7252 2 роки тому +4

    this video really helped me out,now ill pass my TD test

  • @readmymind7503
    @readmymind7503 4 роки тому +14

    This is the Best youtube channel ever to Engineering Drawing !! Thank you so much... Your each and every video help me to do all of my University Assignments... Cheers to Arthur Geometry !! ;-)

  • @lollosfloofy
    @lollosfloofy 2 роки тому +3

    thank you mr. arthur, this was very helpful

  • @chukwuemekavincent6998
    @chukwuemekavincent6998 3 роки тому +6

    Well Its precise and Short. Thank you

  • @NorthernItaly-gm5nl
    @NorthernItaly-gm5nl 8 місяців тому +1

    Saved my life ❤

  • @agnieszkaurban6397
    @agnieszkaurban6397 2 місяці тому +1

    pozdro, polska dziekuje za filmik

  • @zipporahmurigi4623
    @zipporahmurigi4623 3 роки тому +4

    Thank you for this

  • @radoslavangelov6748
    @radoslavangelov6748 2 роки тому +3

    On the point. Nice job!

  • @hawamukabanawanga8502
    @hawamukabanawanga8502 4 роки тому +2

    Thanks

  • @worstchannelever4031
    @worstchannelever4031 2 роки тому +5

    Thanks, have an exam in 20 min lol

  • @homamrostom-z9o
    @homamrostom-z9o 2 місяці тому +1

    What if the two circles have the same radius?

    • @ArthurGeometry
      @ArthurGeometry  2 місяці тому

      ua-cam.com/video/iS7ibtdLYDE/v-deo.html

  • @em0bxnn1ez13
    @em0bxnn1ez13 3 роки тому +14

    wake me up inside.

    • @jimmmy7680
      @jimmmy7680 2 роки тому +6

      The problem with most of engineers is that they are weebs

  • @priyanshkesharwani1199
    @priyanshkesharwani1199 Рік тому +2

    दो असमान वृत्त क और ख की अनुस्पर्धी (बाहरी) उभयनिष्ठ स्पर्ष रेखायें खीचिये

  • @krisdelano7859
    @krisdelano7859 2 роки тому +6

    Need more explanation.. Your discussion is way too fast!

    • @byrondowling9199
      @byrondowling9199 7 місяців тому

      Slow the video down, he’s explaining it good and straight to the point

  • @CarlosFromSchool
    @CarlosFromSchool 3 роки тому +3

    construct parabola

  • @hanneh235
    @hanneh235 4 роки тому +5

    Please help me to understand this😭
    Draw an arc tangent to two unequal circles.
    Given two circles of unequal radii and the Radius r.
    R1= 15 mm
    R2= 25 mm
    R = 20 mm(👈this is the thing that i mean)
    Just really what is R = 20 mm for😭

    • @mono2859
      @mono2859 3 роки тому +2

      what's the distance between the centres?

    • @kevinfoo8031
      @kevinfoo8031 3 роки тому +2

      If R is the inner radius between R1 & R2 then add R1 to R, add R2 to R. With that radius draw an arc from the centres of R1 & R2 respectively. Where both arcs intersect is the centre point for R. For external radius, subtract not add then do the same.

  • @BANDELAIRFANBANDELAIRFAN
    @BANDELAIRFANBANDELAIRFAN 4 місяці тому

    ? O😊

  • @dimaawad9958
    @dimaawad9958 4 роки тому

    Dima

    • @soumi6720
      @soumi6720 3 роки тому

      @@masonhunter2748 your humour broken?

  • @ornguabimbola5344
    @ornguabimbola5344 2 роки тому

    I don't really understand

  • @sodbuster4411
    @sodbuster4411 2 роки тому +4

    Thanks so much for this. I needed to know the surface area of a TO-3 transistor for thermal calculations. With your video, I was able to draw it in a CAD program and query it's surface area.
    en.wikipedia.org/wiki/TO-3