Question

Find the volume of solid generated by revolving the circle x^2+y^2=25 about y axis

Answer 1

equation of circle is ...

x² + y² = 25

from this equation we get, centre of circle is (0,0) and radius of circle is 5 unit. now when we revolve the circle about y - axis. a solid sphere forms as shown in figure.

now volume of spherical solid , V = 4/3πr³ unit³

= 4/3 π (5)³ unit³

= 500π/3 unit³

hence, volume of solid is 500π/3 unit³