Question

Find the surface area of the following figure if it is folded along the dotted lines.(All the measurements are in cm).

• A. 215 cm²
• B. 200 cm²
• C. 190 cm²
• D. 230 cm²

Answer 1

The correct option is A

215 cm²

Surface area of the figure = sum of areas of (I + II + III + IV + V)

= (15$\times$3.5) + (5$\times$3.5) + (15$\times$3.5) + (5$\times$3.5) + (15$\times$5)

= 215 cm${}^2$

Alternate solution

Upon folding we get a cuboid excluding one of the top or bottom faces

Therefore surface area = 2(lb+ bh + lh) – lb = lb + 2h(l+b)

= (15$\times$5) + 7(20) = 215cm${}^2$