According to Means-extremes Property of proportion: If , then
(Cross products)
(Multiply:
)
(Distributive property:
)
According to addition property of equality: Add to 16 each side.
\ (Additive inverse property:
)
(Additive identity property:
)
(Add:
)
(Divide each side by 4)
(Cancel common terms)
(Divide:
)
The value of .