Answer:
line QR
Step-by-step explanation:
Plane QRB is the front face. Plane TSR is the top face. The planes intersect at the top front edge, line QR.
The value of x would be the answer of 25^2 which means it is squared and squaring means a number times itself, so, therefore you have 25x25 which would give you the answer of 625 meaning x=625