Question

4. ADEF is an equilateral triangle.
E
24
20
D
F

Answer 1

By Pythagorean theorem

x²+GF²=EF² ( where G is the point of intersection of perpendicular lines)

now, GF=1/2 EF= 12

x²+12²=24²

x²=24²-12²

x²=432

x=√432

x=12√3

x≈20.78