Question

Fine area of a triangle of sides 9cm,12cm and 15cm

Answer 1

Step-by-step explanation:

area of triangle = 1/2 ×base × height

= 1/2 × 12 × 15

90 ans

Answer 2

Let sides be -

           a = 9 cm , b= 12 cm , c= 15 cm    

Semi-perimeter = a + b + c

                                    2

          S    =  9 + 12 + 15    =   18 cm

                           2

Area = $\sqrt{s(s-a)(s-b)(s-c)$

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

        = $\sqrt{18*9*6*3$

        = $\sqrt{3*3*2*3*3*3*2*3$

        = $3*2*3*3$

        =   $\boxed{54cm^{2}}$

∴ Area of triangle is 54cm²