A rectangular pyramid has a length of 7 cm and a width of 9 cm. Its volume is 231 cubic centimeters. Use the formula for the volume of a pyramid to calculate the height of this pyramid. Show all your work.

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1 answer

The formula for the volume \( V \) of a pyramid is given by:

\[ V = \frac{1}{3} \times \text{Base Area} \times \text{Height} \]

For a rectangular base, the base area \( A \) is calculated as:

\[ A = \text{length} \times \text{width} = 7 , \text{cm} \times 9 , \text{cm} = 63 , \text{cm}^2 \]

Now we'll substitute the known values into the volume formula:

\[ 231 , \text{cm}^3 = \frac{1}{3} \times 63 , \text{cm}^2 \times h \]

We can multiply both sides by 3 to eliminate the fraction:

\[ 3 \times 231 = 63 \times h \]

Calculating \( 3 \times 231 \):

\[ 693 = 63h \]

Next, divide both sides by 63 to solve for \( h \):

\[ h = \frac{693}{63} = 11 , \text{cm} \]

Thus, the height of the pyramid is:

\[ \boxed{11 , \text{cm}} \]