Answer:
We have to use heron’s formula to find the area of the triangle. Here a=7cm, b=9cm and c=12cm s = (a+b+c)/2 = (7+9+12)/2 = 28/2 = 14 Area of the triangle = √s(s-a)(s-b)(s-c) = √14(14-7)(14-9)(14-12) = √14×7×5×2 = √2×7×7×5×2 = √5×(2×2)×(7×7) = 14√5 cm^2 Hence area Of the triangle is 14√5 cm^2.
