Question

If each side of a equilateral triangle is increased by 4 cm and the ratio [4]
of the perimeters of the new equilateral triangle and the given
equilateral triangle is 7 : 5 ,then find the perimeter of the given triangle

Answer 1

Answer:

∴ $x= 10$

Step-by-step explanation:

Side of the given triangle = x

Perimeter of the given triangle = 3x

Side of new triangle = x+4

Perimeter of the new triangle = 3x+12

$\frac{new \Delta}{given \Delta} = \frac{3x+12}{3x} = \frac{7}{5}$

$\frac{x+4}{x} =\frac{7}{5} \\1 +\frac{4}{x} = 1+\frac{2}{5}\\ \frac{4}{x} = \frac{2}{5}$

∴ $x= 10$