The perimeter of a triangle is 54 m and its sides are in the ratio of 5:6 :7.The area of the triangle is
1). 18 sq.m.
2). $54\sqrt{6}$ sq.m.
3). $27\sqrt{2}$ sq.m.
4). 25 sq.m.
Solution:
Given: Perimeter of the triangle = 54 m
Ratio of the sides of the triangle = 5 : 6 : 7
Let the sides be a = 5x , b = 6x , c = 7x.
So, 5x + 6x + 7x = 54 m
18x = 54
x = 54/18
x = 3 m
So, the sides are,
a = 5(3) = 15 m
b = 6(3) = 18 m
c = 7(3) = 21 m
Heron's formula :
Area = √[S(S - a)(S - b)(S - c)] sq.units
where, S = (a + b + c)/2
S = (15 + 18 + 21)/2 = 27
Area = √[27(27 - 15)(27 - 18)(27 - 21)] m²
Area = √[27(12)(9)(6)] m²
Area = √[17496] m²
Area = 54√6 m²
So, the correct option is 2). 54√6 sq.m.