The proportion is .
Apply cross product property: If , then
.
(Cross products)
(Apply distributive property:
)
(Multiply:
)
(Apply distributive property:
)
(Multiply:
)
Apply subtraction property of equality: Subtract 45 from each side.
\ (Apply additive inverse property:
)
(Subtract:
)
(Subtract 27b from each side)
Apply commutative property of addition: a + b = b + a.
\ (Apply additive inverse property:
)
(Subtract:
)
Apply division property of equality: Divide each side by 18.
\ (Cancel common terms)
(Divide:
)
The value of .