Question

Two identical prisms with triangles as base are joined to form a rectangular prism as shown below.

What is the total surface area of the rectangular prism?

• A. $680c{m}^2$
• B. $630c{m}^2$
• C. $1260c{m}^2$
• D. $760c{m}^2$

Answer 1

The correct option is B $630c{m}^2$

After joining the two prism we get a rectangular prism which is also called cuboid.

Total surface area $=2(lb+bh+hl)$

$=2(12\times 5+5\times 15+15\times 12)$

$=2(60+75+180)$

$=2\times 315=630c{m}^2$