9th grade math word prblem

Question

In Triangle DEF, Angle D is 60 degrees, Angle E is 5x degrees, Angle F is 5x degrees, and side EF is 4 inches. What is the value of x? What are the measures of sides FD and DE?

Answer 1

D = 60 degrees

E+F+60 = 180

E+F = 180-60= 120

5x+5x = 120

10x = 120

x = 120/10 = 12 inches

E=F=D = 60 degrees. It's an equilateral triangle with all sides = 4 inches = EF = FD = DE