Question

The circumferences of two concentric circles are given to be $172$ m and $108$ m. find the difference between the radii of the circles.

• A. $12.34$ m
• B. $14.93$ m
• C. $23.47$ m
• D. $10.19$ m

Answer 1

The correct option is D $10.19$ m

Circumference of inner circle=$2\pi r_1$

Circumference of the outer circle= $2\pi r_2$

$2\pi r_1=$108

$r_1=\frac{54}{\pi }$

$2\pi r_2=150$

$r_2=\frac{86}{\pi }$

Difference between radii of circles =$r_2-r_1$

difference=$\frac{86}{\pi }-\frac{54}{\pi }=\frac{32}{\pi }=10.19m$

Hence, Difference between radii is 10.19m.

option D is the answer.