The triangles below are similar.
which similaritiy statement expressess the relationship between the two triangles.
XYZ-QRS
XYZ-RQS
ZXY-QSR
ZXY-QRS

susie has 7 apples

the revenue of the fitness center, y, is the product of two factors: the number of members and the fee paid by each member. there are 320 members now, but number of members goes down by 10 for each $5 increase in fees, so if x is the number of $5 price increases then members is equal to (320 - 10x). since the fee is currently $45, and the fee increases by $5 for every price bump x, the fee is given by (45 + 5x). so, revenue y is given by y = (320 - 10x)(45 + 5x).

cross multiplying, we get :

⇒ (3) × (5) = (9) × (x)

⇒ 15 = 9x