What is the volume of a rectangular prism with a length of 3 2/3ft, a height of 4 1/3ft, and a width of 2 1/4ft?

Write your answer as a mixed number or improper fraction

1 answer

To find the volume of a rectangular prism, we use the formula:

\[ \text{Volume} = \text{length} \times \text{width} \times \text{height} \]

First, we convert the mixed numbers to improper fractions:

  1. Length: \(3 \frac{2}{3}\)

    • Convert: \(3 \times 3 + 2 = 9 + 2 = 11\)
    • Therefore, \(3 \frac{2}{3} = \frac{11}{3}\)
  2. Height: \(4 \frac{1}{3}\)

    • Convert: \(4 \times 3 + 1 = 12 + 1 = 13\)
    • Therefore, \(4 \frac{1}{3} = \frac{13}{3}\)
  3. Width: \(2 \frac{1}{4}\)

    • Convert: \(2 \times 4 + 1 = 8 + 1 = 9\)
    • Therefore, \(2 \frac{1}{4} = \frac{9}{4}\)

Now, we can calculate the volume:

\[ \text{Volume} = \frac{11}{3} \times \frac{13}{3} \times \frac{9}{4} \]

First, multiply the numerators:

\[ 11 \times 13 \times 9 = 1287 \]

Next, multiply the denominators:

\[ 3 \times 3 \times 4 = 36 \]

Thus, we have:

\[ \text{Volume} = \frac{1287}{36} \]

Now, simplify \(\frac{1287}{36}\):

To simplify, we need to divide both the numerator and denominator by their greatest common divisor (gcd). The \(gcd(1287, 36)\) can be found as follows:

  1. Prime factorization of \(36 = 2^2 \times 3^2\).

  2. Check divisibility of \(1287\) by \(3\):

    • Sum of the digits: \(1 + 2 + 8 + 7 = 18\) (which is divisible by \(3\)): \[ 1287 \div 3 = 429 \]

    Check \(429\): \[ 4 + 2 + 9 = 15 \quad (divisible , by , 3) \Rightarrow 429 \div 3 = 143 \] \(143 = 11 \times 13\)

Thus, we find that \(1287 = 3^2 \times 11 \times 13\).

Now, simplification:

\[ \frac{1287}{36} = \frac{3^2 \times 11 \times 13}{2^2 \times 3^2} = \frac{11 \times 13}{2^2} = \frac{143}{4} \]

Finally, express \(\frac{143}{4}\) as a mixed number:

\[ 143 \div 4 = 35 \quad \text{with a remainder of } 3 \]

So, the mixed number is:

\[ 35 \frac{3}{4} \]

Thus, the volume of the rectangular prism is:

\[ \boxed{\frac{143}{4}} \quad \text{or } 35 \frac{3}{4} \text{ ft}^3 \]