Question

The cost of fencing a triangular ground having the sides 15 m, 8 m and x m at the rate of ₹ 3 per m is :

• A. ₹ 220
• B. ₹ 120
• C. ₹ 140
• D. ₹ 100

Answer 1

The correct option is B

₹ 120

The triangle given is a right angled triangle with right angle at B.

Using Pythagoras' theorem we get :

$x^2$ = $A{B}^2$ + $B{C}^2$

$\Rightarrow$ $x^2$ = ${15}^2$ + $8^2$

$\Rightarrow$ $x^2$ = 225 + 64 = 289

$\Rightarrow$ x = 17

Now we can calculate the perimeter by adding all the three sides

Perimeter = 17 + 15 + 8 = 40 m

$\therefore$ Cost of fencing at ₹ 3 per metre = 40 $\times$ 3 = ₹ 120