1.
Areas Related To Circles
Problems based on
Perimeter and area of a circle
Chapter : Areas Related To Circles Website: www.letstute.com

2.
Problems based on
Perimeter and area of a circle
Q) Find the circumference and area of the circle of radius
7.2cm.
Given: Radius of the circle = 7.2cm
To Find: a) Circumference of the circle = ?
b) Area of the circle = ? O
7.2 cm
Chapter : Areas Related To Circles Website: www.letstute.com

3.
Problems based on
Perimeter and area of a circle
Solution: Let the radius of the circle be ‘r’
r=7.2cm ---------- (given)
a) Circumference = 2πr
=2x22x7.2cm
7
= 45.26 cm
b) Area = πr2
= 22x7.2x7.2cm2
7
= 162.93 cm2
O
7.2 cm
Chapter : Areas Related To Circles Website: www.letstute.com

4.
Problems based on
Perimeter and area of a circle
Result: a) Circumference= 45.26cm
b) Area= 162.93cm2
Hence, the circumference of the circle is
and its area is
45.26cm
162.93 cm2
O
7.2 cm
Chapter : Areas Related To Circles Website: www.letstute.com

5.
Problems based on
Perimeter and area of a circle
Q) The diameter of a watermelon slice is 8cm. Find its
perimeter.
Given: Diameter = 8cm
To Find: Perimeter of the slice = ?
8cm
Chapter : Areas Related To Circles Website: www.letstute.com

6.
Problems based on
Perimeter and area of a circle
Solution: Let ‘r’ be the radius of the watermelon slice.
8cm
r = Diameter = 8cm = 4cm
2 2
Perimeter = 1x 2πr+2r
of the slice 2
22
1

   4  2 4


2
2
=20.57 cm



7
20.57cm
Result: Perimeter of the slice = 20.57 cm
Hence, the perimeter of the watermelon slice is
Chapter : Areas Related To Circles Website: www.letstute.com

7.
Problems based on
Perimeter and area of a circle
Q) The difference between the circumference and diameter of a
wheel is 18cm. Find the radius of the wheel.
Given: Circumference - diameter=18cm
To Find: Radius of the wheel = ?
O
? cm
Chapter : Areas Related To Circles Website: www.letstute.com

8.
Problems based on
Perimeter and area of a circle
Solution: Let the radius of the wheel be ‘r’
Circumference-Diameter = 18cm ------- (Given)
2πr-2r = 18cm
2r(π-1) = 18cm
2r 
1

= 18cm

2r 
= 18cm
2r x 15 = 18cm


 
22 7
7
7
r = 18x7 cm
2x15



22
7


O
? cm
Chapter : Areas Related To Circles Website: www.letstute.com

9.
Perimeter and area of a circle
= 9x7 cm
15
= 3x7 cm
5
= 21 cm
5
= 4.2cm
Problems based on
Result: Radius of the wheel= 4.2cm
Hence, the radius of the wheel is 4.2cm
O
? cm
Chapter : Areas Related To Circles Website: www.letstute.com

10.
Problems based on
Perimeter and area of a circle
Q) A wire is in the form of a circle of radius 50cm. It is bent
into a square. Determine the side of the square.
O
Before
Given : Radius of the circle = 50 cm
To Find: Side of the square = ?
Chapter : Areas Related To Circles Website: www.letstute.com

11.
Problems based on
Perimeter and area of a circle
Solution: Let the radius of the circle be ‘r’
r = 50cm ---------- (given)
Length of the wire = Circumference of the circle
= 2πr
= 2x22x50cm
7
= 2200 cm
7
= 314.28cm
O
Before
Chapter : Areas Related To Circles Website: www.letstute.com

12.
Problems based on
Perimeter and area of a circle
Let ‘x’ be the side of the square.
Perimeter of the square = Length of the wire (circumference)
4x = 314.28
x = 314.28
4
x = 78.57 cm
X cm
After
Hence, the side of the square is
78.57cm
Chapter : Areas Related To Circles Website: www.letstute.com

13.
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