Question

What is the total surface area of the drawing?

Answer 1

Total surface area equals area of 5 rectangular faces + 2 pentagonal faces

Area of 5 rectangular faces

$=5 \times 6 \times 9 km^2$

$=270 km^2$

Area of 2 pentagonal faces can be found by drawing 5 isosceles triangles with height as shown in the diagram and multiply the result by 2.

$=5 \times \frac{1}{2} \times 9 \times 6.2 \times 2km^2$

$=279km^2$

The toatal surface area is

$=270+279=549 km^2$

The correct answer is A