The proportion is .
Apply cross product property: If , where
.
(Apply distributive property:
)
(Multiply:
)
(Subtract 1125 from each side)
(Apply commutative property of addition:
)
(Apply additive inverse property:
)
(Apply additive identity property:
)
(Add:
)
(Divide each side by negative 75)
(Quotient of two same signs is positive)
(Cancel common terms)
(Divide:
)
The solution is .