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Question
Find the height and volume of a cone with slant height of 41 feet and a radius of 40 feet. Use 3.14 for pi. Click Here for Help Video 2. Click HERE for help video. Click HERE for Formulas Sheet.

1 answer

To find the height and volume of a cone with a given slant height and radius, we can use the following formulas:

  1. Height (h) can be found using the Pythagorean theorem: \[ s^2 = r^2 + h^2 \] where \( s \) is the slant height, \( r \) is the radius, and \( h \) is the height.

  2. Volume (V) of the cone is given by the formula: \[ V = \frac{1}{3} \pi r^2 h \]

Given:

  • Slant height (\( s \)) = 41 feet
  • Radius (\( r \)) = 40 feet
  • Use \( \pi = 3.14 \)

Step 1: Find the height

Using the Pythagorean theorem: \[ 41^2 = 40^2 + h^2 \] Calculating \( 41^2 \) and \( 40^2 \): \[ 1681 = 1600 + h^2 \]

Now, solving for \( h^2 \): \[ h^2 = 1681 - 1600 \] \[ h^2 = 81 \]

Now, take the square root to find \( h \): \[ h = \sqrt{81} = 9 \text{ feet} \]

Step 2: Find the volume

Now that we have the height, we can calculate the volume: \[ V = \frac{1}{3} \pi r^2 h \] Substituting the values: \[ V = \frac{1}{3} \cdot 3.14 \cdot (40)^2 \cdot 9 \] Calculating \( (40)^2 \): \[ (40)^2 = 1600 \] Now substitute this back: \[ V = \frac{1}{3} \cdot 3.14 \cdot 1600 \cdot 9 \]

Calculating \( 1600 \cdot 9 \): \[ 1600 \cdot 9 = 14400 \] Now substitute back into the volume equation: \[ V = \frac{1}{3} \cdot 3.14 \cdot 14400 \]

Now, calculate \( 3.14 \cdot 14400 \): \[ 3.14 \cdot 14400 = 45144 \] Finally, \[ V = \frac{1}{3} \cdot 45144 \approx 15048 \]

Final Answers:

  • Height \( h = 9 \) feet
  • Volume \( V \approx 15048 \) cubic feet