math
posted by Emma on .
What is the Surface area of a glass bead that has the diameter of 11m? Express your answer to the nearest square mm.
A glass bead would be a sphere. So the formula for that is>
SA = 4ðr^2
= 4ð(5.5^2)
= 380mm^2

is the diameter 11mm? Then
radius= .0055m
radius^2= 5.5E3 ^ 2=30.25 E6m
4PIr^2= about 12*30.25E6 m