Question

what solid 3d object is produced by rotating the quarter-circle 360° about line m?
choose 1 answer:
a a sphere with radius 10 units
b a sphere with diameter 10 units
c a hemisphere with radius 10 units
d a hemisphere with diameter 10 units
what is a hemisphere?

Explanation:

A quarter - circle, when rotated 360° about a line (assuming the radius of the quarter - circle is 10 units), forms a hemisphere. A full circle rotated 360° forms a sphere, but a quarter - circle (which is a quarter of a full circle) rotated 360° will form a hemisphere. If the radius of the quarter - circle is 10 units, the hemisphere formed will have a radius of 10 units. Option A is incorrect because a quarter - circle won't form a full sphere. Option B: a sphere with diameter 10 units would have a radius of 5 units, which doesn't match the quarter - circle's radius (assuming the quarter - circle has radius 10). Option D: a hemisphere with diameter 10 units would have a radius of 5 units, which is incorrect. So the correct answer is the one with a hemisphere of radius 10 units.

Answer:

C. A hemisphere with radius 10 units