The triangles are said to be similar, so the measures of sides in the larger triangle are proportional to the measures of sides in the smaller triangle. The measures of the two long sides have the ratio 182:65, so we expect the ratio of the shortest sides to be the same:
... ? : 45 = 182 : 65 . . . or . . . ?/45 = 182/65
Multiplying the equation by 45 gives us
... ? = 45·(182/65) = 126
The appropriate choice is ...
... C. 126