What is perimeter ?
The perimeter of any shape can be found by labelling and adding together each side.
Length of each side should be included when we calculate perimeter.
Find the perimeter of the following:
Problem 1 :
Solution :
Given, side a = 5 cm
Perimeter of a triangle = 3a
= 3 × 5
= 15 cm
So, perimeter of a triangle is 15 cm.
Problem 2 :
Solution :
Given, length l = 4 cm and width = 7 cm
Perimeter of a rectangle = 2(l + w)
= 2(4 + 7)
= 2(11)
= 22 cm
So, perimeter of a rectangle is 22 cm.
Problem 3 :
Solution :
Given, a = 5 cm, b = 12 cm
By using Pythagorean Theorem,
c² = a² + b²
c = √(a² + b²)
c = √(5² + 12²)
c = √(25 + 144)
c = √169
c = 13 cm
Perimeter of a triangle = a + b + c
= 5 + 12 + 13
= 30 cm
So, perimeter of a triangle is 30 cm.
Problem 4 :
Solution :
Let a = 6 cm, b = 4 cm, c = 6 cm and d = 10 cm
Perimeter of a Trapezoid = a + b + c + d
= 6 + 4 + 6 + 10
= 26 cm
So, Perimeter of a Trapezoid is 26 cm.
Problem 5 :
Solution :
Let a = 5 cm, b = 12 cm
By using Pythagorean Theorem,
c² = a² + b²
c = √ (a² + b²)
c = √(5² + 12²)
c = √(25 + 144)
c = √169
c = 13 cm
Perimeter of a triangle = a + b + c
= 5 + 12 + 13
= 30 cm
So, perimeter of a triangle is 30 cm.
Problem 6 :
Solution :
Let a = 4 cm, b = 5 cm
By using Pythagorean Theorem,
c² = a² + b²
c = √(a² + b²)
c = √(4² + 5²)
c = √(16 + 25)
c = √41
c = 6.4 cm
Perimeter of shapes = a + b + c + d
= 4 + 2 + 7 + 6.4
= 19.4 cm
So, perimeter of shapes is 19.4 cm.
Problem 7 :
Kim decides to get fit by running laps of a nearby shopping complex. Its dimensions are shown in the diagram alongside.
How many laps does he have to complete to run 13 km in total?
Solution :
Let a = 400 m and b = 300 m
By using Pythagorean Theorem,
c² = a² + b²
c = √a² + b²
c = √400² + 300²
c = √160000 + 90000
c = √250000
c = 500 m
Perimeter of shapes = 700 + 700 + 500 + 400 + 300
= 2600 m
1 km = 1000 m
13 km = 13000 m
= 13000/2600
= 5 laps
May 21, 24 08:51 PM
May 21, 24 08:51 AM
May 20, 24 10:45 PM