PROBLEMS ON FINDING PERIMETER OF TRIANGLE

Work out the perimeter of each of these equilateral triangles

Problem 1 :

Solution :

Perimeter of equilateral triangle P = 3a

P = 3 × 8

 P = 24 cm

So, the perimeter of equilateral triangle is 24 cm.

Problem 2 :

Solution :

Perimeter of equilateral triangle P = 3a

P = 3 × 4.5

 P = 13.5 cm

So, the perimeter of equilateral triangle is 13.5 cm.

Problem 3 :

Solution :

Perimeter of equilateral triangle P = 3a

P = 3 × 71

 P = 213 cm

So, the perimeter of equilateral triangle is 213 cm.

Problem 4 :

Solution :

Perimeter of equilateral triangle P = 3a

P = 3 × 0.26

 P = 0.78 cm

So, the perimeter of equilateral triangle is 0.78 cm.

Calculate the perimeter of each of these isosceles triangles

Problem 5 :

Solution :

Perimeter of  isosceles triangle P = 2a + b

Here a is length of equal sides.

P = 2(22) + 14

P = 44 + 14 

 P = 58 cm

So, the perimeter of isosceles triangle is 58 cm.

Problem 6 :

Solution :

Perimeter of  isosceles triangle P = 2a + b

P = 2(7) + 10

P = 14 + 10 

 P = 24 cm

So, the perimeter of isosceles triangle is 24 cm.

Problem 7 :

Solution :

Perimeter of  isosceles triangle P = 2a + b

P = 2(9) + 8.5

P = 18 + 8.5 

 P = 26.5 cm

So, the perimeter of isosceles triangle is 26.5 cm.

Problem 8 :

Solution :

Perimeter of  isosceles triangle P = 2a + b

25 = 2(9) + x

25 = 18 + x

25 - 18 = x

x = 7 cm 

So, the missing side of the above triangle is 7 cm.

Problem 9 :

Solution :

From the picture, it is clear. The given triangle is equilateral triangle.

36 = 3x

36 = 3x

36/3 = x

x = 12 cm 

So, side length of equilateral triangle is 12 cm.

Problem 10 :

Solution :

Perimeter of  isosceles triangle P = 2a + b

79 = 2(x) + 35

79 = 2x + 35

79 - 35 = 2x

2x = 44

x = 44/2

x = 22 cm

So, the missing side is 22 cm.