the volume of a cone is given to us through the formula:
pi x radius squared x height
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3
you need to find the radius which is half the diameter, so 5 inches
the height is given, 10 inches
sub the values into the formula
π x r^2 x h
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3
π x 5^2 x 10
= -----------------
3
= 261.8 inches cubed (to 1 dp)