2007-06-22 01:57:58 · 5 answers · asked by jagdish b 1 in Science & Mathematics ➔ Mathematics
Surface Area = 4 π r ²
No diagrams required!
2007-06-22 02:02:58 · answer #1 · answered by Como 7 · 1⤊ 0⤋
The surface area of a sphere of radius 'r' is:
surface area = 4Pi r2
The value of Pi can never be known exactly, so surface areas of spheres cannot be calculated exactly. Common approximations for Pi are: 3.14.
Example 1 if 'r' = 5 for a given sphere, and Pi = 3.14, then the surface area of the sphere is:
Example:
surface area = 4Pi r2
= 4 Ã 3.14 Ã 52
= 314
If the surface area of the sphere is known, then the radius can be calculated like this:
r = SqRoot of SurfaceArea / 4Pi
Example: If the surface area of a sphere is 500, and Pi = 3.14
r = SqRoot of 500 / (4 x 3.14)
r = SqRoot of 39.81
r = 6.31
2007-06-22 09:46:20 · answer #2 · answered by AnswerMan 2 · 0⤊ 0⤋
well you can draw a sphere and show the radius on the diagram then use the formulas above to work it out
2007-06-22 09:08:15 · answer #3 · answered by <3 ...sEz... <3 3 · 0⤊ 0⤋
surface area = 4 * pi * r^2
2007-06-22 09:04:51 · answer #4 · answered by topsyk 3 · 1⤊ 0⤋
Volume = 4/3 PI * r^3
Surface Area = Dvolume/DR = 4 PI r^2
2007-06-22 09:04:18 · answer #5 · answered by telsaar 4 · 0⤊ 1⤋