Question

calculate the surface area of the right prism. 1 cm 2 cm 3 cm a) 36 cm² b) 6 cm² c) 22 cm² d) 28 cm²

Explanation:

Step1: Identify surface - area formula

The surface - area formula for a rectangular prism is $SA = 2(lw+lh + wh)$, where $l$ is the length, $w$ is the width, and $h$ is the height. Here, $l = 3$ cm, $w = 2$ cm, and $h = 1$ cm.

Step2: Calculate $lw$

$lw=3\times2 = 6$ cm².

Step3: Calculate $lh$

$lh = 3\times1=3$ cm².

Step4: Calculate $wh$

$wh=2\times1 = 2$ cm².

Step5: Substitute into formula

$SA=2(6 + 3+2)$.
First, add the values inside the parentheses: $6 + 3+2=11$ cm².
Then, multiply by 2: $SA = 2\times11=22$ cm².

Answer:

C. $22$ cm²