Question

The sum of the length, breadth and height of a uniform cross sectional cuboid is $20cm$, and the height of its diagonal is $17cm$. Find the area of its total surface.

• A. $259c{m}^2$
• B. $269c{m}^2$
• C. $279c{m}^2$
• D. $111c{m}^2$

Answer 1

The correct option is D $111c{m}^2$

The sum of length, breadth and height $=a+b+c=20cm$
Diagonal $=\sqrt{a^2+b^2+c^2}=17$
Squaring on both sides, we get
$a^2+b^2+c^2={17}^2=289$
Surface area $=289c{m}^2$