Question

Find the surface area of a table weight whose net is labelled with dimensions and base area as shown below.

• A. 196 sq cm
• B. 208 sq cm
• C. 198 sq cm
• D. 217 sq cm

Answer 1

The correct option is D 217 sq cm

The given net forms a square pyramid.




It contains one square base and 4 lateral triangular faces.

Base of the triangle = 7 cm

Height of the triangle = 12 cm

Area of a triangular face = $\frac{1}{2}$$\times$ base $\times$ height

= $\frac{1}{2}$ $\times$ 7 $\times$ 12 = 42 sq cm

Total area of 4 triangular faces = 4 $\times$ 42 = 168 sq cm



Base area = 49 sq cm

Total surface area of the square pyramid = Base area + area of 4 triangular faces

= 49 + 168 = 217 sq cm

Hence, the total surface area of square pyramid = 217 sq cm