Question

Sides of triangle are in ratio 1:3 1:4 1:5 and its perimeter is 94 cm find the area of the triangle

Answer 1

so, the sides have lengths 3x,4x,5x

You know that 3x+4x+5x = 94
Before you go to too much trouble, recall that a 3-4-5 triangle is a right triangle. That makes things a bunch easier.