Question

NEED ANSWER FAST

Which of the following shows a correct method to calculate the surface area of the cylinder?

cylinder with diameter labeled 2.8 feet and height labeled 4.2 feet

SA = 2π(2.8)2 + 2.8π(4.2) square feet
SA = 2π(1.4)2 + 2.8π(4.2) square feet
SA = 2π(2.8)2 + 1.4π(4.2) square feet
SA = 2π(1.4)2 + 1.4π(4.2) square feet

Answer 1

The correct method to calculate the surface area of the cylinder is:

SA = 2πr² + 2πrh

where r is the radius of the cylinder's base, h is the height of the cylinder, and π is approximately equal to 3.14.

In this problem, the diameter of the cylinder is labeled as 2.8 feet. The radius of the cylinder is half of the diameter, so the radius is 1.4 feet. The height of the cylinder is labeled as 4.2 feet.

Using the formula for surface area, we can substitute the values to obtain:

SA = 2π(1.4)² + 2π(1.4)(4.2) square feet

Simplifying this equation, we get:

SA = 2π(1.96) + 2π(5.88) square feet

SA = 3.92π + 11.76π square feet

SA = 15.68π square feet

Therefore, the correct answer is not listed. The correct method to calculate the surface area of the cylinder is SA = 2πr² + 2πrh where r is the radius of the cylinder's base, h is the height of the cylinder, and π is approximately equal to 3.14.

Answer 2

The correct method to calculate the surface area of the cylinder is:

SA = 2πr² + 2πrh

where r is the radius of the base of the cylinder and h is the height of the cylinder.

Using the given information that the diameter is labeled 2.8 feet, we can find the radius as:

r = diameter/2 = 2.8/2 = 1.4 feet

and the height is labeled as 4.2 feet.

Substituting these values into the surface area formula gives:

SA = 2π(1.4)² + 2π(1.4)(4.2) square feet

Simplifying the expression gives:

SA = 9.24π square feet

Therefore, the correct method to calculate the surface area of the cylinder is option (b): SA = 2πr² + 2πrh, and the surface area of the cylinder with a diameter of 2.8 feet and height of 4.2 feet is 9.24π square feet.