The radius R of a sphere is 8.1cm. Calculate the sphere's surface area A.

The surface area A of a sphere can be calculated using the formula:

A = 4πR²

where:

• A is the surface area,
• R is the radius of the sphere,
• π is a mathematical constant whose approximate value is 3.14159.

Given that the radius R of the sphere is 8.1 cm, we can substitute R = 8.1 cm into the formula:

A = 4π(8.1 cm)²

Now, calculate the square of the radius:

(8.1 cm)² = 65.61 cm²

Substitute this value back into the formula:

A = 4π * 65.61 cm²

Now, multiply the values:

A = 4 * 3.14159 * 65.61 cm²

A = 1037.87844 cm²

So, the surface area of the sphere is approximately 1037.88 cm².