The correct option is C 3754√3m2
Let the sides of the triangle be a, b and c.
Given that the sides are in the ratio 3 : 5 : 7.
Let a = 3k, b = 5k, c = 7k, where k is any natural number.
Now, perimeter of the triangle is 75 m.
⇒a+b+c=75
⇒3k+5k+7k=75
⇒15k=75
⇒k=5
∴a=15m,b=25m,c=35m
∴ Semi-perimeter, (s) = a+b+c2
=752
∴ Area of a triangle = √s(s−a)(s−b)(s−c)
=√752(752−15)(752−25)(752−35)
=√752×452×252×52
=3754√3m2
Hence, the correct answer is option (c).