The volume of a cone is 253 π cm3

. What is the volume of a sphere if its radius is the same as the cone’s and the height of the cone is equal to the sphere’s diameter

7 answers

To solve the problem, we need to first determine the radius and height of the cone based on the given volume, then we will use that information to find the volume of the sphere.

  1. The volume \( V \) of a cone is given by the formula:

    \[ V = \frac{1}{3} \pi r^2 h \]

    We know that the volume of the cone is \( 253 \pi , \text{cm}^3 \). Therefore, we can set up the equation:

    \[ \frac{1}{3} \pi r^2 h = 253 \pi \]

    Dividing both sides by \( \pi \):

    \[ \frac{1}{3} r^2 h = 253 \]

    Multiplying both sides by 3:

    \[ r^2 h = 759 \]

  2. From the problem, we are told that the height of the cone \( h \) is equal to the diameter of the sphere. Since the radius of the sphere \( r \) is the same as the radius of the cone, we have:

    \[ h = 2r \]

  3. Now substituting \( h = 2r \) into the equation \( r^2 h = 759 \):

    \[ r^2 (2r) = 759 \]

    Simplifying this:

    \[ 2r^3 = 759 \]

    Dividing both sides by 2:

    \[ r^3 = \frac{759}{2} = 379.5 \]

    Taking the cube root to find \( r \):

    \[ r = \sqrt[3]{379.5} \]

    Now we calculate \( r \):

    \[ r \approx 7.32 , \text{cm} \quad (\text{using a calculator}) \]

  4. The sphere's diameter is \( 2r \):

    \[ h = 2r \approx 2 \times 7.32 \approx 14.64 , \text{cm} \]

  5. The volume \( V \) of a sphere is given by the formula:

    \[ V = \frac{4}{3} \pi r^3 \]

    Substituting \( r^3 \approx 379.5 \):

    \[ V \approx \frac{4}{3} \pi (379.5) \]

    Now calculating \( V \):

    \[ V \approx \frac{4}{3} \times 3.14159 \times 379.5 \approx 1595.69 \pi , \text{cm}^3 \]

Thus, the volume of the sphere is approximately \( 1595.69 \pi , \text{cm}^3 \).

The volume of a cone is 25/3 π cm3
. What is the volume of a sphere if its radius is the same as the cone’s and the height of the cone is equal to the sphere’s diameter

To solve the problem, we will first determine the dimensions of the cone (the radius \( r \) and height \( h \)) from the given volume, then calculate the volume of the sphere based on those dimensions.

  1. Volume of the Cone: The formula for the volume \( V \) of a cone is:

    \[ V = \frac{1}{3} \pi r^2 h \]

    We know that the volume of the cone is given as \( \frac{25}{3} \pi , \text{cm}^3 \). Setting up the equation:

    \[ \frac{1}{3} \pi r^2 h = \frac{25}{3} \pi \]

    Dividing both sides by \( \pi \):

    \[ \frac{1}{3} r^2 h = \frac{25}{3} \]

    Multiplying both sides by 3:

    \[ r^2 h = 25 \]

  2. Cone Height in terms of Radius: From the problem, we are told that the height of the cone \( h \) is equal to the diameter of the sphere. Since the radius of the sphere \( r \) is the same as the radius of the cone, we know:

    \[ h = 2r \]

  3. Substituting for Height: Now we substitute \( h \) into the equation we derived from the cone's volume:

    \[ r^2 (2r) = 25 \]

    This simplifies to:

    \[ 2r^3 = 25 \]

    Dividing both sides by 2:

    \[ r^3 = \frac{25}{2} \]

    Taking the cube root to find \( r \):

    \[ r = \sqrt[3]{\frac{25}{2}} \approx 2.924 , \text{cm} \quad (\text{using a calculator}) \]

  4. Calculate Height: The sphere's diameter is \( h \):

    \[ h = 2r = 2 \times \sqrt[3]{\frac{25}{2}} \approx 5.848 , \text{cm} \]

  5. Volume of the Sphere: The volume \( V \) of a sphere is given by the formula:

    \[ V = \frac{4}{3} \pi r^3 \]

    From above, we have:

    \[ r^3 = \frac{25}{2} \]

    Substituting \( r^3 \) into the volume formula:

    \[ V = \frac{4}{3} \pi \left(\frac{25}{2}\right) \]

    Simplifying:

    \[ V = \frac{4 \cdot 25}{3 \cdot 2} \pi = \frac{100}{6} \pi = \frac{50}{3} \pi , \text{cm}^3 \]

Hence, the volume of the sphere is:

\[ \boxed{\frac{50}{3} \pi , \text{cm}^3} \]

A sculptor created a design by carving a cone out of a cylinder. The cone and cylinder share the same radius and height. If the volume of the cylinder before removing the cone is 54 in.3
, what is the volume of the amount remaining

To find the volume of the sculpture after the cone has been carved out of the cylinder, we'll first need to determine the volume of the cone and then subtract that volume from the volume of the cylinder.

  1. Volume of the Cylinder: The volume \( V \) of a cylinder is given by the formula:

    \[ V_{\text{cylinder}} = \pi r^2 h \]

    We know the volume of the cylinder is \( 54 , \text{in}^3 \).

  2. Volume of the Cone: The volume \( V \) of a cone is given by the formula:

    \[ V_{\text{cone}} = \frac{1}{3} \pi r^2 h \]

  3. Finding the Volume of the Remaining Sculpture:

    • To find the volume of the remaining sculpture after the cone has been carved out, we can subtract the volume of the cone from the volume of the cylinder.

    • First, let's denote the volume of the cylinder as \( V_{\text{cylinder}} = 54 , \text{in}^3 \).

    • Assume the cylinder has a height \( h \) and radius \( r \).

    • Since both the cone and the cylinder have the same radius and height, the height of the cylinder \( h \) can be expressed from the volume of the cylinder:

    \[ V_{\text{cylinder}} = \pi r^2 h = 54 \]

    • We will use this equation later, but first, let's calculate the volume of the cone using its relationship to the cylinder.
  4. Find the Volume of the Cone:

    The volume of the cone in terms of cylinder dimensions is:

    \[ V_{\text{cone}} = \frac{1}{3} V_{\text{cylinder}} = \frac{1}{3} \times 54 = 18 , \text{in}^3 \]

  5. Volume of Remaining Sculpture:

    Now, we subtract the volume of the cone from the volume of the cylinder:

    \[ V_{\text{remaining}} = V_{\text{cylinder}} - V_{\text{cone}} = 54 - 18 = 36 , \text{in}^3 \]

Thus, the volume of the amount remaining after the cone has been carved out is:

\[ \boxed{36 , \text{in}^3} \]

An engineer wants to know the volume of the following object composed of a hemisphere and a cone. She knows the height of the cone is equal to the diameter of the hemisphere, and the volume of the cone is 12 m3
. What is the volume of the whole object

To find the total volume of the object composed of a hemisphere and a cone, we will follow these steps:

  1. Determine the Dimensions of the Cone: We know the volume of the cone, which is given as \( V_{\text{cone}} = 12 , \text{m}^3 \). The volume of a cone is given by the formula:

    \[ V_{\text{cone}} = \frac{1}{3} \pi r^2 h \]

    Let's denote the radius of the cone and the hemisphere as \( r \) and the height of the cone as \( h \). According to the problem, the height of the cone is equal to the diameter of the hemisphere, which means:

    \[ h = 2r \]

  2. Substituting the Height into the Volume Formula: We can substitute \( h \) into the volume formula for the cone:

    \[ 12 = \frac{1}{3} \pi r^2 (2r) \]

    Simplifying this, we get:

    \[ 12 = \frac{2}{3} \pi r^3 \]

    To isolate \( r^3 \), we will multiply both sides by \( \frac{3}{2\pi} \):

    \[ r^3 = \frac{12 \cdot 3}{2\pi} = \frac{36}{2\pi} = \frac{18}{\pi} \]

    Thus, we have:

    \[ r = \sqrt[3]{\frac{18}{\pi}} \]

  3. Volume of the Hemisphere: The volume of a hemisphere is given by:

    \[ V_{\text{hemisphere}} = \frac{2}{3} \pi r^3 \]

    We now know \( r^3 = \frac{18}{\pi} \), so we can substitute it into the volume of the hemisphere:

    \[ V_{\text{hemisphere}} = \frac{2}{3} \pi \left(\frac{18}{\pi}\right) = \frac{2}{3} \cdot 18 = 12 , \text{m}^3 \]

  4. Total Volume of the Object: The total volume of the object (the hemisphere plus the cone) is:

    \[ V_{\text{total}} = V_{\text{hemisphere}} + V_{\text{cone}} = 12 + 12 = 24 , \text{m}^3 \]

Therefore, the total volume of the whole object is:

\[ \boxed{24 , \text{m}^3} \]