Question

Find the total surface area of the triangular prism.

• A. $748$ $c{m}^2$
• B. $944$ $c{m}^2$
• C. $1008$ $c{m}^2$
• D. $840$ $c{m}^2$

Answer 1

The correct option is C $1008$ $c{m}^2$

The triangular prism has a triangular base.
Area of the triangular base $=\frac{1}{2}\times Base\times Height$

$=\frac{1}{2}\times (5+9)\times 12$

$=84$ $c{m}^2$

The lateral surface area $=15\times 20+13\times 20+20\times (9+5)$
$=(15+13+14)\times 20$
$=42\times 20$
$=840$ $c{m}^2$
The total surface area $=$ Lateral surface area $+2\times$ Area of the base

$=840+2\times 84$

$=840+168$

$=1008$ $c{m}^2$

The total surface area of the prism is $1008$ $c{m}^2$.