Question

a triangle with given two sides 18 cm and 10 cm respectively and the perimeter is 42 cm , area is ____
(a)20 rootover11 cm²
(b) 19rootover 11cm² (c)22 rootover 11 cm² (d) 21 rootover 11 cm²


please answer fast with explanation​

Answer 1

Let a,b and c be the sides of the triangle

a = 18    b = 10     c = ?

a+b+c=42

18+10+c = 42

 c = 14

Area = √s(s-a)(s-b)(s-c) = √21(3)(11)(7) = √7×3×3×11×7 = 21√11

Answer 2

Answer:

area of triangle = 21√11cm^2