Question

Q.9. Find the area of a triangle whose sides are respectively 9 cm, 12 cm and 15 cm. ​

Answer 1

Answer:

Step-by-step explanation:

let a , b , c be the sides of the triangle respectively

a = 9 cm

b = 12 cm

c = 15 cm

s = $\frac{a + b + c}{2}$

  = $\frac{9 + 12 + 15}{2}$

  = $\frac{36}{2}$

  = 18 cm

Area of the triangle  = $\sqrt{s(s - a)(s - b)(s - c)}$

                                  = $\sqrt{18(18 - 9)(18 - 12)(18 - 15)}$

                                  = $\sqrt{18(9)(6)(3)}$

                                   = $\sqrt{(2)(3)(3)(3)(3)(2)(3)(3)}$

                                   = 2 * 3 * 3 * 3

                                   = 54 $cm^{2}$