Find the missing length indicated. x=

x = 120

Step-by-step explanation:

Here we have 3 triangles, one big and two smaller ones, one at the left and other at the right.

Now, the right sides is shared by the right smaller triangle and the big triangle, if this length is Z, we have that (using the angle in top of it, A, such that 64 is adjacent to A.)

Cos(A) = 64/Z

Cos(A) = Z/(64 +225)

We can take the quotient of those two equations and get:

Then:

Z = √(18,496) = 136.

now, we have that for the smaller triangle one cathetus is equal to 64 and the hypotenuse is equal to 136.

Then, using the Pythagorean theorem:

64^2 + x^2 = 136^2

x = √(136^2 - 64^2) = 120