Question

unit 1 summative (area/perimeter/volume/surface area
find the surface area of a rectangular prism with dimensions 5 m × 4 m × 3 m.
○ 94 cm²
○ 94 m²
○ 62 m²
○ 54 m²

Explanation:

Step1: Recall the formula for the surface area of a rectangular prism

The formula for the surface area \( SA \) of a rectangular prism with length \( l \), width \( w \), and height \( h \) is \( SA = 2(lw + lh + wh) \).
Here, \( l = 5 \, \text{m} \), \( w = 4 \, \text{m} \), and \( h = 3 \, \text{m} \).

Step2: Calculate each term inside the parentheses

First, calculate \( lw \): \( lw = 5\times4 = 20 \, \text{m}^2 \)
Then, calculate \( lh \): \( lh = 5\times3 = 15 \, \text{m}^2 \)
Next, calculate \( wh \): \( wh = 4\times3 = 12 \, \text{m}^2 \)

Step3: Sum the terms and multiply by 2

Sum the terms: \( lw + lh + wh = 20 + 15 + 12 = 47 \, \text{m}^2 \)
Multiply by 2: \( SA = 2\times47 = 94 \, \text{m}^2 \)

Answer:

B. \( 94 \, \text{m}^2 \)