Question

A cuboid is formed of 3 edges measuring $3,4$ and $5cm$. It is sliced into two identical solids by a plane through a diagonal of the smallest of the faces. The surface area of the sliced section is:

• A. $12c{m}^2$
• B. $15c{m}^2$
• C. $20c{m}^2$
• D. $25c{m}^2$

Answer 1

The correct option is D $25c{m}^2$

Area of sliced section $DBFH=DB\times BF$
$D{B}^2=A{D}^2+A{B}^2+4^4+3^3=16+9=25$
$\Rightarrow DB=5$
$\therefore$ Required area $=(5\times 5)=25c{m}^2.$