Question

Find the surface area of the right prism. Round to the nearest whole number.

Answer 1

Answer:

$\large\boxed{S.A.=96\ cm^2}$

Step-by-step explanation:

We have:

(1) two trapezoids with bases b₁ = 7cm and b₂ = 5cm and the height h = 4cm

(2) three rectangles 3 cm × 7 cm, 3 cm × 4 cm and 3 cm × 5 cm.

The formula of an area of a trapezoid:

$A=\dfrac{b_1+b_2}{2}\cdot h$

Substitute:

$A=\dfrac{7+5}{2}\cdot4=24\ cm^2$

Calculate the areas of the rectangles:

$A_1=(3)(7)=21\ cm^2\\\\A_2=(3)(4)=12\ cm^2\\\\A_3=(3)(5)=15\ cm^2$

The Surface Area:

$S.A.=(2)(24)+21+12+15=96\ cm^2$