Question

(29) Two equal sides of a triangle are 5cm less than twice the third side. If the perimeter
of the triangle is 90 cm, find the length of its sides.
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Answer 1

Question:

Two equal sides of a triangle are 5 cm less than twice the third side. If the perimeter  of the triangle is 90 cm, find the length of its sides.

Answer:

The length of the sides of the triangles are _ 35 cm, 35 cm and 20 cm.

Given:

The length of the two equal sides are 5 cm less than the third side.

The perimeter of the triangle is 90 cm.

To find:

The length of the sides of the triangle.

Explanation:

Let, the length of the third side of the triangle be, 'n'.

∴ The length of each equal sides = (n×2)-5

                                                       = 2n-5

∴ Perimeter = (Sum of the three sides)

                   = n+(2n-5)+(2n-5)

                   = 5n-10

∴ According to the problem:

5n-10 = 90

⇒ 5n = 90+10

⇒ n = 100/5

⇒ n = 20 cm.

∴ The length of the third side is 20 cm.

∴ The length of each equal sides = (20×2)-5 cm

                                                      = 40-5 cm

                                                       = 35 cm.

∴ The length of each equal sides is 35 cm.