Question

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Answer 1

Given

The radius of a semicircle ⇒ 7 cm

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To Find

The area of two such semicircles.

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Solution

Formula to find area of semicircle is ⇒ $\dfrac{\pi r^{2} }{2}$

So first we will find the area of one semicircle and then two.

Radius ⇒ 7 cm

Area of Semicircle ⇒ $\dfrac{\frac{22}{7}\times (7)^{2} }{2}$

⇒ $\dfrac{\frac{22}{7}\times 49 }{2}$

⇒ $\dfrac{\frac{22}{7\div 7 }\times 49\div 7 }{2}$

⇒ $\dfrac{22 \times 7 }{2}$

⇒ $\dfrac{154}{2}$

⇒ 77 cm²

∴ The area of 1 semicircle is 77 cm²

The area of two such semicircles ⇒ 77 × 2

⇒ 154 cm²

∴ The area of both the semicircles is 154 cm² in total.

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Answer 2

Given:

Radius of semicircle = 7cm

To Find:

Area of two such semicircles.

Solution:

$\sf{Area \:of \:semicircle=}{\dfrac{\pi{{r}^2}}{2}}$

$\sf{{Area \:of \:two \:semicircles=}{\dfrac{\pi{{r}^2}}{2}}\times 2}$    [in case of semicircles with same radius]

$\sf{\therefore Area =}{\pi{{r}^2}}$

$\sf{{\implies}{\dfrac{22}{7}}\times 7\times7}$

$\sf{{\implies}{22 \times 7}}$

$\sf{\implies 154cm^2}$

Therefore, area of two semicircles with radius 7 cm is 154cm².