A solid is in the shape of a cone standing on a hemisphere with both

their radii being equal to 1 cm and the height of the cone is equal to
its radius. Find the volume of the solid in terms of π.

1 answer

To find the volume of the solid, we first need to calculate the volume of both the cone and the hemisphere separately, and then add them together.

  1. Volume of the Hemisphere:

    The volume \( V_h \) of a hemisphere is given by: \[ V_h = \frac{2}{3} \pi r^3 \] where \( r \) is the radius of the hemisphere. In this case, the radius \( r = 1 \) cm. Substituting this value into the formula: \[ V_h = \frac{2}{3} \pi (1)^3 = \frac{2}{3} \pi \text{ cm}^3 \]

  2. Volume of the Cone:

    The volume \( V_c \) of a cone is given by: \[ V_c = \frac{1}{3} \pi r^2 h \] where \( r \) is the radius of the base of the cone and \( h \) is the height of the cone. In this case, the radius \( r = 1 \) cm, and the height \( h = 1 \) cm (since the height of the cone is equal to its radius). Substituting these values into the formula: \[ V_c = \frac{1}{3} \pi (1)^2 (1) = \frac{1}{3} \pi \text{ cm}^3 \]

  3. Total Volume of the Solid:

    The total volume \( V_{total} \) of the solid is the sum of the volume of the hemisphere and the volume of the cone: \[ V_{total} = V_h + V_c \] Now we can substitute the volumes we calculated: \[ V_{total} = \frac{2}{3} \pi + \frac{1}{3} \pi \]

    Combining these fractions: \[ V_{total} = \left(\frac{2}{3} + \frac{1}{3}\right) \pi = \frac{3}{3} \pi = \pi \text{ cm}^3 \]

Thus, the total volume of the solid in terms of \( \pi \) is: \[ \boxed{\pi} \text{ cm}^3 \]