What is the surface area of the ramp in square feet and if each square foot of wood on the ramp is sold for three dollars how much would the ramp sell for

We know that
[surface area of the ramp]=10*16+8*16+6*16+2*[6*8/2]
[surface area of the ramp]=160+128+96+48> 432 ft²

the answer Part a) is 
the surface area of the ramp is 432 ft²

if 1 ft² is sold for> $3
 432 ft²> x
x=432*3> x=$1296 

the answer Part b)  is
$1296