Help! "Semicircle" country is invaded by so many right-angled triangles!
The army of the "Semicircle" country need your help.
They said: "∠AJH=156° and AJ=JH. ∠BAG and ∠BHG are separated into 5 equal parts. Their weakest part is at ∠DAH. If we able to determine the angle, we could destroy them immediately!"
So, help them to determine ∠DAH.
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Since triangle A J H is isosceles, ∠ J A H = ∠ J H A = 1 2 .
Since ∠ A J H and ∠ B J A are supplementary, ∠ B J A = 2 4 ,
Since ∠ B J A and ∠ B A J are complementary (they are the non-right angles of right triangle B A J ), ∠ B A J = 6 6 .
Since ∠ B A J = ∠ B A G is divided in 5 equal parts, and ∠ D A J is 5 3 of ∠ B A J , ∠ D A J = 3 9 . 6 .
∠ D A H = ∠ D A J + ∠ J A H = 3 9 . 6 + 1 2 = 5 1 . 6 .