Question

The edges of a triangular board are 6cm, 8cm and 10cm. The cost pf painting it at the rate of 9 paise per $c{m}^2$ is

• A. ₹ 2.00
• B. ₹ 2.16
• C. ₹ 2.44
• D. ₹ 2.80

Answer 1

The correct option is B

₹ 2.16

Let $a=6cm,b=8cm,c=10cm$

$s=\frac{a+b+c}{2}=\frac{6+8+10}{2}=12$

Area of triangular board $=\sqrt{12\left(6\right)\left(4\right)\left(2\right)}$

$=24c{m}^2$

Required cost $₹\frac{24\times 9}{100}=₹2.16$