Given:
A triangle with vertices A(0,0), B(6,0), and C(0,9) is rotated 360 about the y-axis.
To find:
The volume of the figure.
Solution:
Points A(0,0) and C(0,9) lies on the y-axis. Length of AC is 9 units.
Points A(0,0) and B(6,0) lies on the x-axis. Length of AB is 6 units.
If a triangle with vertices A(0,0), B(6,0), and C(0,9) is rotated 360 about the y-axis, then it will form a cone with radius 6 units and height 9 units.
Volume of a cone is
[tex]V=\dfrac{1}{3}\pi r^2h[/tex]
where, r is radius of the base and h is vertical height of the cone.
Putting r=6 and h=9, we get
[tex]V=\dfrac{1}{3}\pi (6)^2(9)[/tex]
[tex]V=\pi (36)(3)[/tex]
[tex]V=108\pi[/tex]
Therefore, the volume of the figure is [tex]108\pi[/tex] sq. units.
