and . Also and . If and , what is the area (to the nearest unit) of the blue shaded triangles?
As shown in the diagram above,Diagram is not drawn to scale.
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Firstly, using Pythagoras' Theorem, we can say that: B C = 8 2 + 1 5 2 B C = 6 4 + 2 2 5 = 2 8 9 = 1 7 Therefore: △ B C D = 2 1 7 × 4 = 2 6 8 = 3 4 Now, using right-triangle trigonometry, we know that S i n ( θ ) = H O , therefore: s i n ( 5 3 . 1 ) = H 8 H = s i n ( 5 3 . 1 ) 8 = 1 0 Now if we call the angle at 53.1 point E, then: B E = 1 0 A E = B E 2 − A B 2 = 1 0 2 − 8 2 = 3 6 = 6 C E = 1 5 − A E = 1 5 − 6 = 9 △ B E C = 2 8 × 9 = 2 7 2 = 3 6 Therefore the area of the blue shade is: △ B C D + △ B E C = 3 4 + 3 6 = 7 0 Thank you to everyone who attempted my puzzle!