Area and Perimeter of a Circle

We will discuss the Area and Perimeter of a Circle.

The area (A) of a circle (or circular region) is given by

A = πr2

where r is the radius and, by definition, π = \(\frac{\textrm{Circumference}}{Diameter}\) = \(\frac{22}{7}\) (Approximately).

Area and Perimeter of a Circle

The circumference (P) of a circle, or the perimeter of a circle region, with radius r is given by

P = 2πr

Solved Examples on Area and Perimeter of a Circle:

1. The radius of a circular region is 7 m. Find its perimeter and area. (Use π = \(\frac{22}{7}\))

Solution:

Here r = 7 m. Then,

Perimeter = 2πr = 2 × \(\frac{22}{7}\) × 7 m = 44 m;

Area = πr2 = \(\frac{22}{7}\) × 72 m2 = 154 m2.

 

2. The perimeter of a circular plate is 132 cm. Find its area. (Use π = \(\frac{22}{7}\))

Solution:

Let the radius of the plate be r. Then,

Perimeter = 2πr

⟹ 132 cm = 2 × \(\frac{22}{7}\) × r

⟹ 132 cm = \(\frac{44}{7}\) × r

⟹ \(\frac{44}{7}\) × r = 132 cm

⟹ r = 132 × \(\frac{7}{44}\)

⟹ r = \(\frac{924}{44}\)

⟹ r = 21 cm.

Therefore, area of the plate = πr2 = \(\frac{22}{7}\) × 212 cm2

                                        = \(\frac{22}{7}\) × 441 cm2

                                        = \(\frac{9702}{7}\) cm2

                                        = 1386 cm2






10th Grade Math

From Area and Perimeter of a Circle to HOME PAGE




Didn't find what you were looking for? Or want to know more information about Math Only Math. Use this Google Search to find what you need.



Share this page: What’s this?

Recent Articles

  1. Adding 1-Digit Number | Understand the Concept one Digit Number

    Apr 26, 24 01:55 PM

    Add by Counting Forward
    Understand the concept of adding 1-digit number with the help of objects as well as numbers.

    Read More

  2. Subtracting 2-Digit Numbers | How to Subtract Two Digit Numbers?

    Apr 26, 24 12:36 PM

    Subtracting 2-Digit Numbers
    In subtracting 2-digit numbers we will subtract or minus a two-digit number from another two-digit number. To find the difference between the two numbers we need to ‘ones from ones’ and ‘tens from

    Read More

  3. 1st Grade Word Problems on Subtraction | Subtracting 2-Digit Numbers

    Apr 26, 24 12:06 PM

    1st Grade Word Problems on Subtraction
    In 1st grade word problems on subtraction students can practice the questions on word problems based on subtraction. This exercise sheet on subtraction can be practiced by the students to get more ide…

    Read More

  4. Subtracting 1-Digit Number | Subtract or Minus Two One-Digit Number

    Apr 26, 24 11:21 AM

    Cross Out 6 Objects
    In subtracting 1-digit number we will subtract or minus one-digit number from one-digit number or one-digit number from 2-digit number and find the difference between them. We know that subtraction me…

    Read More

  5. Perimeter of a Square | How to Find the Perimeter of Square? |Examples

    Apr 25, 24 05:34 PM

    Perimeter of a Square
    We will discuss here how to find the perimeter of a square. Perimeter of a square is the total length (distance) of the boundary of a square. We know that all the sides of a square are equal. Perimete…

    Read More