Question

Find the circumference of a circle whose diameter is 42cm

Answer 1

Step-by-step explanation:

Circumference of a Circle = 2πr

and, radius, r = d/2 = 42/2 = 21 cm

Then, Circumference of circle = 2 × (22/7) × 21 = 132 cm

Answer 2

Given :

• diameter of a circle = 42 cm

To find :

• circumference of the circle

Formula used:

• Radius of circle = diameter / 2

• circumference of the circle = 2×π × radius

Solution :

To find circumference first we will find radius of the circle :-

$\implies \: Radius \: of \: circle = \dfrac{diameter}{2}$

put diameter = 42

$\implies \: Radius \: of \: circle = \dfrac{42}{2}$

$\implies \: Radius \: of \: circle = \dfrac{21}{1}$

therefore, radius = 21 cm

Now we will find circumference :-

$circumference = 2 \times \pi \times radius$

now put :-

• π = 22/7
• radius = 21 cm

$\implies \: circumference = 2 \times \pi \times radius$

$\implies circumference = 2 \times \dfrac{22}{7} \times 21$

$\implies circumference = 2 \times \dfrac{22}{1} \times 3$

$\implies circumference = 2 \times {22} \times 3$

$\implies circumference = 44 \times 3$

$\implies circumference = 132 {cm}$

Answer : 132 cm

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$\large\bf\red{Learn\:More}$

Area of circle = πr²

Circumference of circle = 2πr

Area of square = (side)²

perimeter of square = 4× side

area of Rhombus = 1/2(diagonal 1)(diagonal 2)

Area of rectangle = length × breadth

Perimeter of rectangle = 2( length + breadth)

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