Question

if the perimeter of a semi circle protactor is 108 find the diameter of protactor​

Answer 1

Let radius=r

Perimeter of protractor=half of circumference+diameter

πr+2r

Given, perimeter =108

πr+2r=108

r(π+2)=108

r(22/7+2)=108

r(22+14/7)=108

r(36/7)=108

r=108*(7/36)

r=3*7

r=21

Therefore, diameter2r=2*21=42cm

Answer 2

Answer:

5.55cm is the radius of the semicircle

Step-by-step explanation:

(π*r*r)+2*r=108

22r^2+14r-756=0

11r^2+7r-378=0

r=-7+-√47+16632/22

=-7+-129.14/22

radius cannot be -ve so

129.14-7/22 is the answer

ie.5.55cm