MATH
posted by Vince .
Triangle DEF is similar to triangle PQR. Side DE measures 3, side EF measures 7 and side FD measures 9. Side PQ measures 5x – 25 and side QR measures 6x + 4. Find the value of x.

Since triangle DEF similar to triangle PQR. Therefore, their corresponding sides are in the ratio.
DE/EF=PQ/QR
3/7=5x25/6x + 25
On solving the equation we x = 11