Question

Given: △FKL, FK= a
m∠F=45°, m∠L=30°
Find: FL

Answer 1

The sum of angles of a triangle is 180°, so m∠K = 180° -45° -30° = 105°.

The Law of Sines tells you

... FL/sin(∠K) = FK/sin(∠L)

Solving for FL, we get

... FL = FK·sin(∠K)/sin(∠L)

... FL = a·sin(105°)/sin(30°) = a·sin(105°)/(1/2)

... FL = 2a·sin(105°) ≈ 1.93185a