The surface area of a sphere is 86Л(pie)ft^2. What is the diameter of the sphere?

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The surface area of a sphere is 86Л(pie)ft^2. What is the diameter of the sphere?

2006-06-05 13:43:17 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics

4 answers

18.5472 ft

2006-06-05 13:54:55 · answer #1 · answered by sammy 3 · 0⤊ 0⤋

SA = 4*Ï*r^2

if SA = 86Ï, then

86Ï = 4Ïr^2

divide both sides by 4Ï

21.5 = r^2

square-root of both sides,

r = +- 4.637

but, since it is a measurement, we want the positive answer

r = 4.637 ft

diameter is twice the radius, therefore diamter = 9.274 ft

2006-06-05 21:27:37 · answer #2 · answered by ledezmajr 3 · 0⤊ 0⤋

A = 4pi(r^2)
86pi = 4pi(r^2)
21.5 = r^2
r = SQRT 21.5
r = 4.637 ft

So the diameter is 4.637*2 = 9.274 ft

2006-06-05 23:47:44 · answer #3 · answered by Kemmy 6 · 0⤊ 0⤋

SA = 4 (pi) r^2

2006-06-05 21:05:58 · answer #4 · answered by davidosterberg1 6 · 0⤊ 0⤋