Question

There is a slide in a children park. The front side of the slide has been painted and a message "ONLY FOR CHILDREN" is written on it as shown in figure. If the sides of the triangular front wall of the slide are $9m,8m$ and $3m$, then find the area which is painted in colour.

• A. $2\sqrt{35}$ $m^2$
• B. $4\sqrt{35}$ $m^2$
• C. $2\sqrt{31}$ $m^2$
• D. $3\sqrt{35}$ $m^2$

Answer 1

The correct option is A $2\sqrt{35}$ $m^2$

Area of triangle $=\sqrt{s(s-a)(s-b)(s-c)}$.
For triangle with sides 9 m, 8 m and 3 m, $s=\frac{9+8+3}{2}=10m$
Area of the triangle $=\sqrt{10(10-9)(10-8)(10-3)}$

$=\sqrt{10\times 1\times 2\times 7}$

$=\sqrt{5\times 2\times 2\times 7}$

$=2\sqrt{35}{m}^2$