8. The corresponding angles of similar triangles are congruent. Angle U corresponds to angle R, so the value of x will be the value of the unmarked angle in ∆PRQ. The sum of angles is 180°, so the unmarked angle (x) has measure ...
... x = 180° - 60° - 40° = 80° . . . . matches selection A
9. The ratio of the lengths of the original to its image is the same in all cases. The appropriate choice is ...
... B. AB/A'B' = BC/B'C'
The other choices have mixed ratios that don't make any sense.
10. The parallel base makes ∆RTU ~ ∆RQS and divides RQ in the same proportion it divides RS. The appropriate choice here is ...
... C. RT/TQ = RU/US
