Problems related to area and perimeter of square and circle Part- 2

Let's Memorize:

1) Area of square = `L^{2}`	3) Area of circle = `\pi r^{2}`
2) Perimeter of square = 4L	4) Perimeter of circle = 2`\pi`r

Note: `\color{red} {\pi = 3.14 or \frac{22}{7}}`

Square

Q1 A square is 5cm long, find its area and perimeter.

Q2 Find the area and perimeter of a square shape field that is 12.5 m long. Also, find the length of the wire to fence 5 times.

Q3 The area of a square garden is 100 `m^{2}`. Find the cost of it fencing it 4 rounds at Rs 25/m.

Solution,

Area of square garden = 100 `m^{2}`

In order to fence, we need to know its perimeter but length is missing. So let's work on that.

Perimeter = ? x (say)

Length = ? y (say)

We know,

        Area of square = `L^{2}`

or,    100 = `y^{2}`

or,    `\sqrt{100}` = y

or,    10 = y

∴        L = 10 cm

Again, Let's find its perimeter.

        Perimeter = 4L

or,    x = 4 x 10

or,    x = 40 

∴        Perimeter = 40 cm

Required length of wire = Perimeter x 4 rounds

                                        = 40 x 4

                                        = 160 m

∴   Cost     = 160m x Rs25/m

                  = Rs 4000

Q4 A square field is 64m long. Find its perimeter.

Q5 The perimeter of a square is 4.28cm. Find its area.

Q6 The perimeter of a square is 16m, Calculate its area.

Circle

Please note: Radius = `\frac{diameter}{2}` 

                    One Revolution of a wheel = Circumference of the circle.

Q1 

1. The circumference of a circular wheel is 20cm. Find the distance it covers in 3 revolutions.

... Answer is
60 cm

Q2 If the circular wheel has a diameter of 14 cm. Find the distance it covers in 20 revolutions.

Q3 A circular wheel has a radius of 7 cm. Find the distance it covers in 10 revolutions.

Q4 The diameter of a circle is 14 cm. Find its area and perimeter.

What have you learned?

• Area  and perimeter/circumference of a circle
• Perimeter and area of a square
• Problems and solutions based on the area and perimeter/circumference of a circle
• Problems and solutions based on the area and perimeter of a square
• Formula to find the area and perimeter of the circle and rectangle

Are you ready for the Quiz?