An isosceles triangle is one in which two of the sides are the same length. The perimeter of an isosceles triangle is 35 cm. if the length of the congruent sides is 3 times the length of the third side, find the dimensions of the triangle.

perimeter of the isosceles triangle is 35 cm.

let x be one of the congruent sides

therefore the third side is x/3

therefore

x + x + x/3 = 35

7x/3 = 35

7x = 3 x 35

x = 3 x 35/7

x = 15 cm for each congruent side

third side = 15/3 = 5 cm.