Question

D=43cm 3.1.1 Work out the area and perimeter of the semi-circle above​

Answer 1

`\huge \boxed{\mathbb{QUESTION} \downarrow}`

• d = 43cm. Work out the area and perimeter of the ssemi-circle.

`\large \boxed{\mathfrak{Answer \: with \: Explanation} \downarrow}`

Given that,

• diameter (d) = 43 cm
• So, radius (r) = 43/2 = 21.5 cm (radius is equal to half of the diameter in a circle)

Now, let's solve & find the area & perimeter of the semi-circle.

(1) Radius (r) = 21.5 cm

Area of a semi-circle = πr²/2

`\downarrow`

`\tt ( \pi \: r ^(2) )/(2) \\\tt = (3.14 * (21.5) ^(2) )/(2) \\ \tt = (3.14 * 46.25)/(2) \\ \tt = (1451.465)/(2) \\ = \boxed{\boxed{\bf 725.73 \: cm ^(2) }}`

(2) Radius (r) = 21.5 cm

Perimeter of the semi-circle = r (π + 2)

`\downarrow`

`\tt \: r(\pi + 2) \\ = \tt \: 21.5(3.14 + 2) \\ \tt = 21.5(5.14) \\ \tt = 21.5 * 5.14 \\ = \boxed{\boxed{\bf 110.51 \: cm}}`

• NOTE :- Since the value of π is not given in the question, I have taken it as 3.14. The answers can vary a little bit (just a little, so you can round the answers). These are the approximate values.