Question

The perimeter of an isosceles triangle is 65 centimeters. Find the length of the two equal sides when each is 10 centimeters longer than the third side. (An isosceles triangle has two sides of equal length.)

Answer 1

Answer: the length of each of the two equal sides is 25 centimeters

Explanation:

Let x represent the length of each of the two equal sides. This means that the total length of the two longer sides is 2x.

Let y represent the length of the third side.

The perimeter of a triangle is expressed as the sum of the length of each side of the triangle. The perimeter of the isosceles triangle is 65 centimeters. It means that

2x + y = 65 - - - - - - - - - 1

Each of the equal sides is 10 centimeters longer than the third side. This means that

x = y + 10

Substituting x = y + 10 into equation 1, it becomes

2(y + 10) + y = 65

2y + 20 + y = 65

2y + y = 65 - 20

3y = 45

y = 45/3 = 15

Substituting y = 15 into x = y + 10, it becomes

x = 15 + 10 = 25