Question

the radius of a cylindrical gift box is (4x+3) inches. The height of the gift box is three times the radius. what is the surface area of the cylinder? Write your answer as a polynomial in standard form.

Answer 1

We have that
surface area of the cylinder=2*[pi*r²]+[2*pi*r*h]
r=(4x+3)
h=3*r=3*(4x+3)
S=2*[pi*(4x+3)²]+[2*pi*(4x+3)*(3*(4x+3))]------> 2*[pi*(4x+3)²]+[6*pi*(4x+3)²]
S=8*pi*(4x+3)²----> 8*pi*[16x²+24x+9]-----> 402.12 x²+603.19x+226.19

the answer is  S=402.12 x²+603.19x+226.19   (8pi[16x²+24x+9])