Im having trouble with this question, can anyone help me out please? detailed answers would be much appreciated, thankyou! Xxxx
A cube of side 10 cm is melted down and made into ten identical spheres. Calculate the surface area of one of the spheres.
2007-03-03 05:46:43 · 3 answers · asked by Anonymous in Education & Reference ➔ Homework Help
for the 2nd person who answered, where did the 6 come from :S
2007-03-03 06:23:00 · update #1
Each side of a cube is 10cm
thus the volume is (10cm) cubed (to the third)
which is 1000cm^3
One of the spheres has a volume 100cm^3
and since 4/3 (Pi) r^3 is the volume of a sphere and 4(Pi)r^2 is the surface area, we have: 100cm^3 = 4/3 (Pi) r^3; find 4(pi)r^2
300cm^3/r = 4 Pi r^2
and the radius of a 100cm^3 sphere is the cube root of (75/Pi), about 2.879.
Thus 4Pi r^2 =~104.19 cm^2 which is the surface area of our sphere (There's probably a shorter way to do it than the way I did it.)
In response to the added info, an added 6 would probably come from the irrelevant fact that a cube has 6 sides.
2007-03-03 07:05:22 · answer #1 · answered by Paranoid Android 4 · 1⤊ 0⤋
10
2007-03-03 05:53:30 · answer #2 · answered by crispy 2 · 0⤊ 0⤋
Surface area of cube = 10cm x 10cm x 6 = 600cm
Surface area of one sphere = 600/10 = 60cm
2007-03-03 06:06:43 · answer #3 · answered by stacichu7 3 · 0⤊ 0⤋