i cant solve this help pls

16) Since the triangles are similar

Angle A = Angle X

Angle B  = Angle Y

Angle C  = Angle Z

So...to find Y, we have   (180  - 51  - 37 )  =  92°

17)   To find the scale factor from B to C  we have

 After Image Dimension of a Side / Pre-Image Dimension of the corresponding Side

100 / 120   =  10 / 12   =  5/6

18)  Similarly    ...  90 / 72   =  10 / 8  =  5 / 4

18)

90 * the scale factor   =   100

the scale factor   =   100 / 90

the scale factor   =   10/9