Question

PLEASE HELP!

Find the surface area of the cylinder with diameter 20 in. and height 2 in. Use 3.14 for
pi.

Answer 1

`\boxed {\boxed {\sf SA= 753.6 \ in^2}}`

Explanation:

The surface area of a cylinder is found using this formula.

`SA=2 \pi rh+ 2 \pi r^2`

We know the diameter is 20 inches and the height is 2 inches. We must find the radius.

• The radius is half the diameter.
• r= d/2
• r= 20 in /2= 10 in

Now we know that:

`r= 10 \ in \\h= 2 \ in`

Substitute the values into the formula. Also, plug 3.14 in for pi.

`SA=2 (3.14)(10 \ in)(2 \ in)+ 2 (3.14)(10 \ in)^2`

Solve according to PEMDAS: parentheses, exponents, multiplication, division, addition, and subtraction.

Solve the exponent.

• (10 in)²= 10 in * 10 in= 100 in²

`SA=2 (3.14)(10 \ in)(2 \ in)+ 2 (3.14)(100 \ in^2)`

Multiply all the numbers together.

`SA=2 (3.14)(20 \ in^2)+ 2 (3.14)(100 \ in^2)`

`SA=125.6 \ in^2+628 \ in^2`

Add.

`SA= 753.6 \ in^2`

The surface of the cylinder is 753.6 square inches.