How do I find the surface area of these spheres?

1 ⤊

Sphere one: r = 32mm

Sphere two: r = 2.3cm

Sphere three: d = 21mm

Thanks ;:)

2007-01-17 07:47:18 · 5 answers · asked by ☺ Joel ☺ 1 in Science & Mathematics ➔ Mathematics

SA = 4πr²

4π(32)² = 4096π mm²

4π(2.3)² = 21.16π cm²

4π(21/2)² = 441π mm²

2007-01-17 07:53:20 · answer #1 · answered by Jim Burnell 6 · 0⤊ 0⤋

You could use the formula for surface area of a sphere:

SA = 4 pi times r squared

2007-01-17 07:52:35 · answer #2 · answered by hayharbr 7 · 0⤊ 0⤋

A = 4 x pi x r^2

2007-01-17 07:54:12 · answer #3 · answered by Sean S 2 · 0⤊ 0⤋

surface area = 4(pi)r2

Insert r and pi = 3.14 and multiply it out.

12861.44mm^2
66.44cm^2
1384.74mm^2

2007-01-17 07:51:01 · answer #4 · answered by DT 4 · 1⤊ 0⤋

SA = 4(pi)r2

2007-01-17 07:54:04 · answer #5 · answered by shade_ghj 1 · 0⤊ 0⤋