The vertices of triangle $ABC$ lie on the sides of equilateral triangle $DEF$, as shown. If $CD = 5$, $CE = BD = 2$, and $\angle ACB = 90^\circ$, then find $AE$.
Since ∠ACB=90∘, we have ∠ACE=30∘. Also, since △DEF is equilateral, ∠DEF=60∘. Then ∠AED=60∘−30∘=30∘. Furthermore, △AED is isosceles since AD=AE, so ∠ADE=30∘. Since the sum of the angles in a triangle is 180∘, we have ∠AED+∠ADE+∠EAD=180∘ 30∘+30∘+∠EAD=180∘ ∠EAD=120∘.By the Law of Sines in △ADE, we have
So the answer is AE = 10/sqrt(3).