circumference

Circumference & Area of Circle : 

Circumference & Area of Circle Welcome Let’s Learn Student

Circle : 

Circle Definition:- A circle is a shape with all points are at the same distance from the center. The circle to the left has centre at point O. AB is the diameter.

Circumference of circle : 

Circumference of circle The distance around a circle is called the circumference (C). The distance across a circle through the center is called the diameter (d). ? is the ratio of the circumference of a circle to the diameter. Thus, for any circle, if you divide the circumference by the diameter, you get a value equal to ?. Value of ? is approximately 3.1415926535... We use the Greek letter ? (pronounced Pi) to represent this value.

Circumference of circle : 

Circumference of circle Here, AB is the diameter of the Circle and O is the centre of the circle Another formula to write the relation between circumference and diameter is C = ?d This formula is commonly used in problems where the diameter is given and we have to determine the circumference.

Radius of circle : 

Radius of circle In the circle shown in the right, O is the centre of the circle and AO is the radius. Radius is represented by r. Now, the formula to write the relation between circumference and radius is d = 2r This formula is commonly used in problems where the radius is given and we have to determine the circumference. C = 2?r Also,

Let’s Revise : 

Let’s Revise The value of ? is 3.14 The value of ? is also 22/7 The value of ? is determined as where C is the circumference of the circle and d is the diameter of the circle. The Circumference of circle when the radius of the circle is given is Here C is the circumference and r is the radius of the circle. C = 2?r

Example 1:- The radius of a circle is 14 inches. Find its circumference.Solution:- Here, we are given that the radius of circle = 14 inchesWe know thatCircumference of circle = 2?rNow, r = 14 inches ? = 22/7Circumference of circle = 2?r = 2 ?? 22/7 ? 14 = 88 inches : 

Example 1:- The radius of a circle is 14 inches. Find its circumference.Solution:- Here, we are given that the radius of circle = 14 inchesWe know thatCircumference of circle = 2?rNow, r = 14 inches ? = 22/7Circumference of circle = 2?r = 2 ?? 22/7 ? 14 = 88 inches Let’s see an example

Example 2:- The circumference of a circle is 220 inches. Find its radius.Solution:- Here, we are given that the circumference of circle = 220 inchesWe know thatCircumference of circle = 2?rSo, 2?r = 220 2 x 22/7 x r = 220 r = 220 x 7/22 x 1/2 = 35 inchesHence the radius of the circle is 35 inches. : 

Example 2:- The circumference of a circle is 220 inches. Find its radius.Solution:- Here, we are given that the circumference of circle = 220 inchesWe know thatCircumference of circle = 2?rSo, 2?r = 220 2 x 22/7 x r = 220 r = 220 x 7/22 x 1/2 = 35 inchesHence the radius of the circle is 35 inches.

# 1. The radius of a circle is 21 inches. Find its circumference. : 

# 1. The radius of a circle is 21 inches. Find its circumference. Use this space to show your work:

# 2. The radius of a circle is 31.5 inches. Find its circumference. : 

# 2. The radius of a circle is 31.5 inches. Find its circumference. Use this space to show your work:

# 3. The radius of a circle is 52.5 inches. Find its circumference. : 

# 3. The radius of a circle is 52.5 inches. Find its circumference. Use this space to show your work:

# 4. The diameter of a circle is 245 inches. Find its circumference. : 

# 4. The diameter of a circle is 245 inches. Find its circumference. Use this space to show your work:

# 5. The diameter of a circle is 119 inches. Find its circumference. : 

# 5. The diameter of a circle is 119 inches. Find its circumference. Use this space to show your work:

# 6. The circumference of a circle is 154 inches. Find its radius. : 

# 6. The circumference of a circle is 154 inches. Find its radius. Use this space to show your work:

# 7. The circumference of a circle is 22 inches. Find its radius. : 

# 7. The circumference of a circle is 22 inches. Find its radius. Use this space to show your work:

# 8. The circumference of a circle is 55 inches. Find its Diameter. : 

# 8. The circumference of a circle is 55 inches. Find its Diameter. Use this space to show your work:

Area of circle : 

Area of circle In the circle shown in the left with centre O and radius OA , the area of the circle is ?r2. If diameter of the circle is given, the area of the circle is ?d2/4. Important Results:- Area of the circle when its radius is given = ?r2 Area of the circle when its diameter is given = ?d2/4. Unit of Area:- The unit of area is the square of the unit of radius. So, if the unit of radius is ft, then the unit of Area is ft2.

Example 1:- The radius of a circle is 7 inches. Find its area.Solution:- Here, we are given that the radius of circle = 7 inchesWe know thatArea of circle = ?r2Now, r = 7 inches ? = 22/7Hence Area of circle = ?r2 = 22/7 ? (7)2 = 22/7 x 7 x 7 = 154 inches2Hence the area of the circle is 154 inches2. : 

Example 1:- The radius of a circle is 7 inches. Find its area.Solution:- Here, we are given that the radius of circle = 7 inchesWe know thatArea of circle = ?r2Now, r = 7 inches ? = 22/7Hence Area of circle = ?r2 = 22/7 ? (7)2 = 22/7 x 7 x 7 = 154 inches2Hence the area of the circle is 154 inches2. Let’s see an example

Example 2:- The area of a circle is 616 inches2. Find its radius.Solution:- Here, we are given that the area of circle = 616 inches2We know thatNow, Area of circle = ?r2 ?r2 = 616 22/7 x r x r = 616 r2 = 616 x 7/22 r2 = 28 x 7 r = 14 Hence the radius of the circle is 14 inches. : 

Example 2:- The area of a circle is 616 inches2. Find its radius.Solution:- Here, we are given that the area of circle = 616 inches2We know thatNow, Area of circle = ?r2 ?r2 = 616 22/7 x r x r = 616 r2 = 616 x 7/22 r2 = 28 x 7 r = 14 Hence the radius of the circle is 14 inches. Let’s see an example

# 1. The radius of a circle is 10.5 inches. Find its area. : 

# 1. The radius of a circle is 10.5 inches. Find its area. Use this space to show your work:

# 2. The radius of a circle is 17.5 inches. Find its area. : 

# 2. The radius of a circle is 17.5 inches. Find its area. Use this space to show your work:

# 3. The diameter of a circle is 28 inches. Find its area. : 

# 3. The diameter of a circle is 28 inches. Find its area. Use this space to show your work:

# 4. The area of a circle is 2464 inches2. Find its radius. : 

# 4. The area of a circle is 2464 inches2. Find its radius. Use this space to show your work:

# 5. The area of a circle is 924 inches2. Find its diameter. : 

# 5. The area of a circle is 924 inches2. Find its diameter. Use this space to show your work:

# 6. The area of a circle is 550/7 inches2. Find its circumference. Use ? = 22/7 : 

# 6. The area of a circle is 550/7 inches2. Find its circumference. Use ? = 22/7 Use this space to show your work:

# 7. The circumference of a circle is 77 inches. Find its area. : 

# 7. The circumference of a circle is 77 inches. Find its area. Use this space to show your work:

GOODBYE !! Have a Nice evening : 

GOODBYE !! Have a Nice evening