In the right △ A B C with side lengths A B = 2 7 and B C = 3 6 , a square, a rectangle and two circles of the same radius are inscribed.
Input the sum of areas of the square and the rectangle as your answer.
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∠ B A C = α ⟹ ∠ A C B = 9 0 − α and ∠ A E F = 9 0 − α . So, we have, △ A B C ∼ A F E ⟹ A F = 2 7 k and E F = 3 6 k for some constant k > 0 . Also, A B = 2 7 , B C = 3 6 and C A = A B 2 + B C 2 = 4 5 .
LetSimple angle chasing gives, ∠ A E F = 9 0 − α ⟹ ∠ B E L = α ⟹ ∠ B L E = 9 0 − α ∠ A C B = ∠ G I H = 9 0 − α ⟹ G H I = α We conclude that, △ A F E ∼ △ H G I ∼ △ I J C and △ H G I ≅ △ E B L , since they have the same inradius. △ A F E ∼ △ H G I △ H G I ∼ △ I J C △ H G I ≅ △ E B L ⟹ H G A F = G I F E ⟹ 3 6 k 2 7 k = G I 3 6 k ⟹ G I = 4 8 k ⟹ H I = H G 2 + G I 2 = 6 0 k ⟹ I J H G = I C H I ⟹ I J 3 6 k = 4 5 − 1 1 1 k 6 0 k ⟹ I J = 5 3 ( 4 5 − 1 1 1 k ) ⟹ B E = G H = 3 6 k In right-triangle A F E , A E 2 ( 2 7 − 3 6 k ) 2 ( 3 − 4 k ) 2 = A F 2 + E F 2 = ( 2 7 k ) 2 + ( 3 6 k ) 2 = ( 3 k ) 2 + ( 4 k ) 2 Solving the above quadratic equation, gives us k = 3 1 . Therefore, area [ E F G H ] area [ H I J K ] = ( E F ) 2 = ( 3 6 k ) 2 = 1 2 2 = 1 4 4 = H I ⋅ I J = 6 0 k ⋅ 5 3 ( 4 5 − 1 1 1 k ) = 2 0 ⋅ 5 2 4 = 9 6 ⟹ area [ E F G H ] + area [ H I J K ] = 2 4 0
The areas of each of the two congruent circles = 16*pi
27x + 36 y = 972 { 27 x 36 = 972}
y = 12 - 0.75x
y = 1.3333x + 12
y = 1.3333x - 8
y = 4.8
x = 9.6
(x-4)^2 + (y-4)^2 = 16
(x-17.6)^2 + (y-8.8)^2 = 16
All the equations for the figure shown in the problem have been written above.
Area of the Square = 12 x 12 = 144
Area of the Rectangle = 4.8 x 20 = 96
Sum of the area of the square and rectangle = 144+96 = 240.
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First we note that △ A B C is a 3 - 4 - 5 right triangle (this makes things a lot easier).
Label the square D E F G and the rectangle G H I J . Extend F G to meet B C at K . Since the two circles are congruent and the three angles of △ D G H and △ B F K are the same, △ D G H and △ B F K are congruent (this also makes things a lot easier).
Let the side length of square D E F G be a , then D G = B F = a , D H = B K = 3 4 a , and G H = F K = 3 5 a . Let G J = b . We note that △ G J K and △ B F K are similar (makes things easy again), then
G K G J G J ⟹ b = F K B F = 5 3 = 5 3 ⋅ G K = 5 3 ( F K − F G ) = 5 3 ( 3 5 a − a ) = 5 2 a
We have:
A F + F B A F + 5 3 ⋅ F G + G J 4 5 a + 5 3 a + b 2 0 2 5 + 1 2 + 8 a 2 0 4 5 a ⟹ a = A B = A B = 2 7 = 2 7 = 2 7 = 1 2
The sum of areas of the square and rectangle is a 2 + b ⋅ G H = a 2 + 5 2 a ⋅ 3 5 a = 3 5 a 2 = 2 4 0