Question

Find the area of the circle whose dianeter is 28cm 10cm 6.4mm

Answer 1

1) Given

$\bold{Diameter \ of \ the \ circle} = 28 cm\\\bold{Radius \ of \ the \ circle} = 14 cm\\\implies \bold{ Area \ of \ the \ circle }\\= \pi r^{2} \\ = 22/7 * 14 * 14\\ = \boxed{\boxed{\bold{616 cm^{2} }}}}$

                                                               

2) Given

$\bold{Diameter \ of \ the \ circle} = 10 cm\\\bold{Radius \ of \ the \ circle} = 5 cm\\\implies \bold{ Area \ of \ the \ circle }\\= \pi r^{2} \\ = 3.14 * 5 * 5\\ = \boxed{\boxed{\bold{78.5 cm^{2} }}}}$

                                                               

3) Given

$\bold{Diameter \ of \ the \ circle} = 6.4 mm\\\bold{Radius \ of \ the \ circle} = 3.2 mm\\\implies \bold{ Area \ of \ the \ circle }\\= \pi r^{2} \\ =3.14 *3.2 * 3.2\\ = \boxed{\boxed{\bold{32.15 mm^{2} }}}}$

                                                               

Answer 2

Given:

• Measure of three diameters are 28 cm , 10 cm and 6.4 mm

To Find:

• What is the are of three circles?

Solution: Let's find the area of circle with diameter 28 cm.

• Radius = Diameter/2 = 28/2 = 14 cm

★ Area of Circle = πr² ★

$\small\implies{\sf }$ 22/7 x (14)²

$\small\implies{\sf }$ 22/7 x 196

$\small\implies{\sf }$ 4312/7

$\small\implies{\sf }$ 616 cm²

Hence, The area of first circle with diameter 14 cm is 616 cm²

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• In second circle whose diameter is 10 cm •

• Radius = Diameter/2 = 10/2 = 5 cm

★ Area of circle = πr² ★

$\small\implies{\sf }$ 22/7 x (5)²

$\small\implies{\sf }$ 22/7 x 25

$\small\implies{\sf }$ 550/7

$\small\implies{\sf }$ 78.57 cm²

Hence, The area of circle with diameter 10 cm is 78.57 cm²

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• In third circle whose diameter is 6.4 mm •

• Radius = Diameter/2 = 6.4/2 = 3.2 mm

★ Area of circle = πr² ★

$\small\implies{\sf }$ 22/7 x (3.2)²

$\small\implies{\sf }$ 22/7 x 10.24

$\small\implies{\sf }$ 225.28/7

$\small\implies{\sf }$ 32.18 mm²

Hence, The area of circle with Diameter 6.4 mm is 32.18 mm²

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