What is diameter of the circle if the circumference of a circle is 18.6 cm?

If the circumference of a circle is 18.6 cm more than its diameter, then what is the diameter of the circle ?

 

[A] 8.68 cm

[B] 8.84 cm

[C] 7.54 cm

[D] 7.84 cm

 

Answer: A. 8.68 cm

Explanation:  

2πr = 18.6 + (D)
2πr = 18.6 + 2r
2πr - 2r = 18.6
2r (π - 1) = 18.6
2r = 186/10 X 7/15
r = 186/10 X 7/15 X 1/2
=> 1302/300
D = 2 X 1302/300 = 8.68

 

This Question Asked in UP Lekhpal 2015 Exam

Read More>>