Question

Find the perimeter of a semi circle whose diameter is 21cm​

Answer 1

`\boxed{ \boxed{ \bold{ \purple{16.485 \: cm}}}}`

Explanation:

Diameter ( d ) = 21 cm

Radius is just half of the diameter

Radius ( r ) =
`\sf{ (21)/(2) }` = 10.5 cm

Now, let's find the perimeter of a semi - circle :

`\sf (1)/(2) \pi \: r \:`

Plug the values

⇒
`\sf{ (1)/(2) * 3.14 * 10.5}`

Calculate

⇒
`\sf{16.485 \: cm}`

Hope I helped!

Best regards!