I think we have to use Pythagorean Therom here
a² + b² = c²
First we need to know the height of the Triangle (which is YT)
Let "b" be the height YT:
22² + b² = 77²
484 + b² = 5929
b² = 5929 - 484 = 5445
√b² = √(5445)
b = √5445 = 73.79ft
Now that we have the height lets find the missing base(YK):
We are going to use the same formula, but this time to find the base and with a different triangle.
a² + 73.79² = 87.5²
a² + 5444.96 = 7656.25
a² = 7656.25 - 5444.96
a² = 2211.29
√a² = √(2211.29)
a = √2211.29 = 47.02
Now we can add the bases together to find x.
Bases "VY" and "YK"
x = 22+47
x = 69