Answer:
∠ADB≅∠ABC by the Alternate Interior Angles Theorem
∠CAD≅∠ACB by the Alternate Interior Angles Theorem
∠BAD and ∠ADV are supplementary by the Consecutive Interior Angle Theorem
∠ABC and ∠BCD are supplementary by the Consecutive Interior Angle Theorem
c+2 increases linearly with c. That means that if c increases by 1, c+2 will increase by 1; if by 2, c+2 will increase by 2; and so on.
y = c+2 is a "linear function of c."
A room area
Lenght × Width = 16 × 12
= 192 square feet
1 square yard = 9 square feet
so 1 square feet = 1/9 square yard
192 square feet = 192 × 1/9 square yard
= 64/3 square yard
Total cost
$30 × 64/3 = $640