Question

Two concentric circles form a ring. The inner and outer circumference of the ring are 352/7 m and 528/7m respectively.Find the width of the ring.
A) 5
B) 4
C) 3
D) 2

Answer 1

it is correct..!.........

Answer 2

Answer:

option (B) is correct

Step-by-step explanation:

concept:

If R and r are outer and inner radii of a ring

then its width = R - r

Given:

$Outer\:circumferemnce=\frac{528}{7}m \\\\2{\pi}R=\frac{528}{7} \\\\Inner\:circumferemnce=\frac{352}{7}m \\\\2{\pi}r=\frac{352}{7}$

Now,

$2{\pi}R-2{\pi}r=\frac{528}{7}-\frac{352}{7} \\\\2\pi(R-r)=\frac{528-352}{7} \\\\2\pi(R-r)=\frac{176}{7} \\\\\pi(R-r)=\frac{88}{7}\\\\(\frac{22}{7})(R-r)=\frac{88}{7} \\\\R-r=(\frac{88}{7})(\frac{7}{22})$

R - r = 4 m

width of the ring = 4 m