Can you find area of the Blue shaded region? | (Semicircle) |

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  • Опубліковано 10 чер 2024
  • Learn how to find the area of the Blue shaded region. Important Geometry and Algebra skills are also explained: Congruent triangles; area of the sector formula. Step-by-step tutorial by PreMath.com
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КОМЕНТАРІ • 59

  • @ravikrpranavam
    @ravikrpranavam 7 днів тому +3

    Good explanation

    • @PreMath
      @PreMath  7 днів тому +1

      Glad to hear that, Ravi ji 🌹
      Thanks for the feedback ❤️

  • @ahmetylmaz4577
    @ahmetylmaz4577 18 годин тому

    Beautiful question and nice solution

  • @JLvatron
    @JLvatron 7 днів тому +2

    I found a way to solve this but your solution was so elegant!

    • @PreMath
      @PreMath  6 днів тому +1

      Excellent!
      Thanks for the feedback ❤️

  • @abefroman7393
    @abefroman7393 7 днів тому +2

    Elegant solution. Thank you.

    • @PreMath
      @PreMath  7 днів тому

      Glad to hear that!
      You are very welcome!🌹
      Thanks for the feedback ❤️

  • @johnbrennan3372
    @johnbrennan3372 7 днів тому +1

    Very interesting problem.

    • @PreMath
      @PreMath  6 днів тому

      Excellent!
      Glad to hear that!
      Thanks for the feedback ❤️

  • @paullangenkamp
    @paullangenkamp 6 днів тому +1

    Nice!

    • @PreMath
      @PreMath  6 днів тому

      Glad to hear that! 🌹
      Thanks for the feedback ❤️

  • @marioalb9726
    @marioalb9726 День тому +1

    α = 60° ; β = 30°
    A = A2 - A1
    A = ½R² (2α- sin2α) - ½R² (2β - sin 2β)
    A = ½3² (⅔π -√3/2) - ½3² (⅓π - √3/2)
    A = 5,527 - 0,815
    A = 4,71 cm² ( Solved √ )

  • @luigipirandello5919
    @luigipirandello5919 6 днів тому +1

    Beautiful solution. Thank you, sir.

    • @PreMath
      @PreMath  6 днів тому +1

      So nice of you, dear🌹
      You are very welcome!
      Thanks for the feedback ❤️

  • @misterenter-iz7rz
    @misterenter-iz7rz 7 днів тому +2

    Divided by six equal parts 6×30°, the area of the first segment is 1/6×3^2 pi+3^2sqrt(3)×(1/2)=(3/2)pi+(9/2)sqrt(3), the area of the third segment is (3/2)pi-(9/2)sqrt(3), therefore the answer is (9/2) pi-3pi=(3/2)pi.😮 the interesting answer, that is one sixth xircle.

    • @PreMath
      @PreMath  7 днів тому +1

      Excellent!
      Thanks for sharing ❤️

  • @ikvangalen6101
    @ikvangalen6101 6 днів тому +1

    Liked this a lot

    • @PreMath
      @PreMath  6 днів тому

      Excellent!
      Glad to hear that!
      Thanks for the feedback ❤️

  • @marcelowanderleycorreia8876
    @marcelowanderleycorreia8876 6 днів тому

    Brilliant solution!

    • @PreMath
      @PreMath  6 днів тому

      Glad to hear that! 🌹
      Thanks for the feedback ❤️🙏
      Love and prayers from the USA! 😀

  • @garypaulson5202
    @garypaulson5202 6 днів тому +1

    Very clever indeed

    • @PreMath
      @PreMath  6 днів тому

      Glad to hear that! 🌹
      Thanks for the feedback ❤️🙏

  • @prossvay8744
    @prossvay8744 7 днів тому +3

    Area of Blue region=2(30/360)(π)(3^2)=3π/2 square units.=4.71 square units.❤❤❤

    • @PreMath
      @PreMath  7 днів тому +1

      Excellent!
      Thanks for sharing ❤️

  • @santiagoarosam430
    @santiagoarosam430 6 днів тому +1

    Los cuartos de circulo están trisecados en ángulos de 30°.
    Área BNMC =(Sector circular de 120° - Triángulo OBN) - (Sector circular de60° - Triángulo OCM).
    Los triángulos OBN Y OCM tienen igual superficie ---> Área BNMC =Sector 120° - Sector 60° =Sector 60° =π3^2/6 =9π/6 =3π/2.
    Gracias y un saludo cordial.

    • @PreMath
      @PreMath  6 днів тому

      Excellent!🌹
      Thanks for sharing ❤️

  • @quigonkenny
    @quigonkenny 6 днів тому +1

    As the lengths of all 6 arcs are the same, we can determine the angle between rhem, as the full arc of a semicircle is 180°:
    180°/6 = 30°
    Thus CM covers an arc of 2(30°) = 60° and BN covers an arc of 4(30°) = 120°. We can determine the area between them by finding the difference between the circular segment defined by CM and the circular segment defined by BN. The formula for a circular segment is θ/360°πr²-r²sin(θ)/2, or the area of a sector of angle θ minus the corresponding isosceles triangle of side length r. In this case our radius is 6/2 = 3, so we already have all the information we need:
    Blue area:
    A = (θ₁/360°πr²-r²sin(θ₁)/2) - (θ₂/360°πr²-r²sin(θ₂)/2)
    A = (120/360°πr²-r²sin(120)/2) - (60/360°πr²-r²sin(60)/2)
    A = πr²/3 - πr²/6

    • @PreMath
      @PreMath  6 днів тому

      Excellent!
      Thanks for sharing ❤️

  • @teresinhagoulartferreira8370
    @teresinhagoulartferreira8370 6 днів тому +1

    Brilhante solução!!!! Dayvis Jr (Brazil)

    • @PreMath
      @PreMath  6 днів тому

      Fico feliz em ouvir isso! 🌹
      Obrigado pelo feedback ❤️🙏
      Amor e orações dos EUA! 😀

  • @AmirgabYT2185
    @AmirgabYT2185 День тому +1

    S=3π/2≈4,71

  • @stanbest3743
    @stanbest3743 6 днів тому +1

    I did it a clunky way area of sectors then minus the triangle up to the chord then subtract the very top area. Worked out the same way

    • @PreMath
      @PreMath  6 днів тому

      Excellent!
      Thanks for sharing ❤️

  • @zdrastvutye
    @zdrastvutye 5 днів тому

    there is a calculation using the formula, see line 50, and there is a numeric one:
    10 rem print ln(pi^4+pi^5); "aus youtube":vdu5:for a=0 to 15:gcola:print a:next a
    20 print "premath-can you find area of the blue shaded region"
    30 ne=6:nu=15:ne=ne-1:nuk=100:rem anzahl der unterteilungen des halbkreises und nu fstr$vposr die grafik
    40 dia=6:r=dia/2:wt=pi/(ne+1):wo=wt*2:wu=wt:ho=r*sin(wo):hu=r*sin(wu):h=ho-hu
    50 xl=-r*cos(wo):xr=-xl:da=r*r*(wt/2-sin(wt/2)*cos(wt/2)):wud=pi-2*wt:wod=pi-4*wt: print wod*180/pi
    60 lu=r*sqr(2)*sqr(1-cos(wud)):lo=r*sqr(2)*sqr(1-cos(wod))
    70 masx=1200/2/r:masy=850/r:if masx

  • @jimlocke9320
    @jimlocke9320 6 днів тому +1

    The area can also be calculated from the original diagram, without dividing into 2 quarter circles, as follows: Blue region area = (sector BON - ΔBON) - (sector COM - ΔCOM) = (sector BON - sector COM) - (ΔCOM - ΔBON). The difference in areas of the sectors equals the area of a 60° sector, 1/6 the area of the full circle, or (1/6)(π(3)² = 3π/2. ΔCOM is an equilateral triangle, sides equal to the radius of the circle. ΔBON can be divided into 2 30°-60°-90° special triangles with hypotenuse equal to circle's radius, and assembled into an equilateral triangle with sides equal to the radius, so ΔCOM and ΔBON have equal area. Blue region = 3π/2, as PreMath also found.

    • @PreMath
      @PreMath  6 днів тому

      Excellent!
      Thanks for the feedback ❤️

  • @marcgriselhubert3915
    @marcgriselhubert3915 6 днів тому +1

    Turn the whole drawing Pi/2 rad clockwise. The blue area is twice the area of FECB with tha abscissa of F beeing 3.cos(Pi/3) = 3/2, the abscissa of E beeing 3.cos(Pi/6) =(3/2).sqrt(3), and the equation of the circle x^2 + y^2 = 9 or y = sqrt(9 -x^2)
    So the blue area is 2. the integral from 3/2 to (3/2).sqrt(3) of sqrt(9 -x^2) dx, or 6.the integral from 3/2 to (3/2).sqrt(3) of sqrt(1 - (x/3)^2) dx.
    We note x/3 = sin(t), dx = 3.cos(t).dt
    The blue area is then 18. the integral from Pi/6 to Pi/3 of sqrt(1 -sin(t)^2).cos(t) dt, or 18.the integral from Pi/6 to Pi/3 of cos(t)^2 dt, or 9.the integral from Pi/6 to Pi/3 of
    (1 + cos(2.t)).dt.
    Finally 9.(F(Pi/3) - F(pi/6)) with F(t) = t - (1/2).sin(2.t)
    or 9.(Pi/3) - sin((2/3).Pi) - Pi/6) + sin(Pi/3)) = 9.(Pi/3 - Pi/6) = 9.(Pi/6) = (3/2).Pi.
    It's very simple but not easy to write with the computer without special signs.

    • @PreMath
      @PreMath  6 днів тому

      Excellent!
      Thanks for sharing ❤️

  • @aljawad
    @aljawad 6 днів тому +1

    I went straight ahead to integral calculus to reach the same result.

    • @PreMath
      @PreMath  5 днів тому

      Great!
      Thanks for the feedback ❤️

  • @franzvohburger4107
    @franzvohburger4107 6 днів тому

    Die blaue Fläche ist 1/3 der gesamten Fläche. 1,5 π

  • @wackojacko3962
    @wackojacko3962 6 днів тому +1

    Yes! What is the difference of congruent triangles OCE and OBF? ...similar question could be asked, what's the difference between a frog? 🤔

    • @PreMath
      @PreMath  6 днів тому +1

      😀
      Glad to hear that!
      Thanks for the feedback ❤️

  • @pralhadraochavan5179
    @pralhadraochavan5179 6 днів тому +1

    Good morning sir

    • @PreMath
      @PreMath  6 днів тому

      Same to you, dear 🌹❤️

  • @wackojacko3962
    @wackojacko3962 7 днів тому +1

    😉

    • @PreMath
      @PreMath  7 днів тому

      😀
      Thanks ❤️

  • @giuseppemalaguti435
    @giuseppemalaguti435 7 днів тому +1

    Ab=2(9π/4-3π/2)=3π/2

    • @PreMath
      @PreMath  7 днів тому

      Excellent!🌹
      Thanks for sharing ❤️

    • @phungpham1725
      @phungpham1725 7 днів тому

      1/ Area of the blue region = Area of segment BCMN- Area of the small upper white segment.
      2/ Notice that the triangle COM is an equilateral triangle of which the side = radius= 3. Moever, the triangle BON is formed by two special 30-90-60 of which the side is also= radius= 3, which means that the areas of the 2 triangles mention above are equal.
      So, Area of the segment BCMN = Area of sector 120 degree - Area of triangle BON (1)
      Area of small white segment= Area of 60 degree sector- Area of triangle COM (2)
      (1) -(2) ->Area of shaded region= Area of 120 degree sector- Area of 60 degree sector = pi sqr/3- pi sqr/6= 3pi-3 pi/2= 3pi/2 sq units😅

  • @aliturkseven
    @aliturkseven 6 днів тому +1

    blue Area=Semi circle Area - (above white Area+ below white Area)
    above white Area=Area(Sector OCM)-Area(Triangle OCM)=(60/360)*9*Pi - (3*3*sin(60))/2=
    (9*Pi)/6 - ( (9*sqrt(3))/4 )
    below white area=Area(Sector OAB)+Area(Triangle OBN)+Area(sector ONP)
    =(9*Pi/12)+(9*sqrt(3)/4 )+(9*Pi/12)=(9*Pi/6)+(9*sqrt(3)/4 )
    blue Area=Semi circle Area - (above white Area+ below white Area)
    blue Area=(9*Pi/2) - [ (9*Pi)/6 - ( 9*sqrt(3)/4 ) +(9*Pi/6)+(9*sqrt(3)/4 ) ]
    =(9*Pi/2)-[ 18*Pi/6 ]
    =( 27*Pi- 18* Pi)/6 =(9*Pi)/6
    =(3*Pi)/2

    • @PreMath
      @PreMath  6 днів тому

      Excellent!
      Thanks for sharing ❤️

  • @inyomansetiasa
    @inyomansetiasa 7 днів тому +2

    First comment and first like

    • @PreMath
      @PreMath  7 днів тому

      Excellent!
      Thanks ❤️

  • @harrymatabal8448
    @harrymatabal8448 6 днів тому

    Is the blue area a semicircle 😂