Question

two semicircle put together make a circle of diameter 28cm.find its perimeter​

Answer 1

Answer:

88 cm

Step-by-step explanation:

Radius = r; Diameter = d; d = 2r

Perimeter, P = 2πr = πd (π = 3.14 or 22/7)

So, P ⇒ (22/7) × 28 = 88cm

Answer 2

Answer:

Given:

A semicircle of diameter 28 cm

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To find:

The perimeter

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Solution:

The diameter of the semicircle, d = 28 cm

∴ The radius of the semi-circle, r = $\frac{d}{2} = \frac{28}{2} =14cm$

We know the formula of the perimeter of a semicircle is as follows:

Perimeter of a semi - circle =  [ $\frac{1}{2}$ * circumference of the circle ] + [ Diameter ]

Therefore, we get

$Perimeter [ \frac{1}{2} * 2\pi r] + d$

now, by substituting the values in the formula

⇉$Perimeter =[ \frac{1}{2} * 2* \frac{22}{7} * 14 ] + 28$

⇉ $Perimeter = [ \frac{22}{7} * 14 ] + 28$

⇉ Perimeter = [22 * 2 ] + 28

⇉ Perimeter = 44 + 28

⇉Perimeter = 72

Thus, the perimeter of the semi-circle is → 72 cm.

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