Answer:
it is a 60 30 90 triangle so basically 2y is = x
21² + y² = x²
441 + y² = x²
y = x/2 (2y = x)
441 + x²/4 = x²
4x² = 1764 + x²
3x² = 1764
x = exact is 24.248711306 simplied square root would just be 14√3
2y = 14√3
y = 7√3
exact wouldd be 12.124355653
