Math Problem Statement

a rectangular pyramid has a length of 7 cm and a width of 9. the total volume is 231. what is the height of the pyramid

Solution

The formula for the volume of a rectangular pyramid is:

V=13×Base Area×HeightV = \frac{1}{3} \times \text{Base Area} \times \text{Height}

Step 1: Identify the known values

  • Length of the base (ll) = 7 cm
  • Width of the base (ww) = 9 cm
  • Volume (VV) = 231 cm³

The base area is:

Base Area=l×w=7×9=63cm2\text{Base Area} = l \times w = 7 \times 9 = 63 \, \text{cm}^2

Step 2: Solve for the height

Substitute into the volume formula:

231=13×63×h231 = \frac{1}{3} \times 63 \times h

Simplify:

231=21×h231 = 21 \times h

Solve for hh:

h=23121=11cmh = \frac{231}{21} = 11 \, \text{cm}

Final Answer:

The height of the pyramid is 11 cm.


Would you like a step-by-step explanation of another similar problem? Here are some related questions:

  1. How do you find the volume of a triangular pyramid?
  2. If the height were doubled, what would the new volume be?
  3. How do you calculate the surface area of a rectangular pyramid?
  4. What happens to the volume if the base length and width are halved?
  5. How can this formula be applied to irregular pyramids?

Tip: Always confirm the base area calculation before solving for height in volume problems.

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Math Problem Analysis

Mathematical Concepts

Geometry
Volume of a Pyramid

Formulas

Volume of a rectangular pyramid: V = (1/3) × Base Area × Height
Base Area = Length × Width

Theorems

Volume of a pyramid formula

Suitable Grade Level

Grades 7-9