Find the missing length indicated. i’ve been really struggling with this for some reason, i just don’t understand at all.

Answer:
60 units
Step-by-step explanation:
Mark the angles as shown.
Given BC = x
Let us assume:
Baudhayan theorem states that
In ∆ BMC,<BMC = 90°. So by Baudhayan theorem
In ∆BMA <BMA = 90° . So by Baudhayan theorem
In ∆ ABC <ABC = 90°. So by Baudhayan theorem
Here AC = AM + CM = 64+36 = 100
Add equation (i) and (ii):
From equation (iii),
Subtract 5392 from both sides:
Divide both sides by 2:
Square root both sides:
Putting the value of m in equation (i),
Square root both sides: