Question

. A wire of length of 36 cm is bent in the form of a semi-circle. What is the radius of the semi-circle?​

Answer 1

Step-by-step explanation:

So, the perimeter of a semicircle is πr+d, where r = radius and d = diameter of a semicircle. The length of a wire which bent in the form of a semicircle is equal to the perimeter of a semicircle. ∴ The radius of the semicircle is 7cm.

Answer 2

Answer:

7cm

Step-by-step explanation:

perimeter of wire and semicircle is same so

$\frac{2\pi r}{2} + d = 36 \\ \\ \pi r + 2r = 36 \\ r(\pi + 2) = 36 \\ \frac{22r + 14r}{7} = 36 \\ \\ \frac{36r}{7} = 36 \\ \\ 36r = 36 \times 7 \\ r = 7$

the diameter is also counted for perimeter

because πr is for only outside one including inside diameter πr+d

refer attachment to get what I want to say