Question

THE CIRCUMFERENCE OF TWO CONCENTRIC CIRCLES FORMING A RING ARE 88 CM AND 66 CM RESPECTIVELY.WHAT IS THE WIDTH OF THE RING?

Answer 1

Let circumference of two circles be C1 and C2,and radius of two circles be r1 and r2.
C1=88cm
2Πr1=88cm
2×22/7r1=88cm
r1=88×7/2×22
r1= 14cm
C2=66cm
2Πr2=66cm
2×22/7×r2=66cm
r2=66×7/2×22
r2=21/2cm
width of ring = area of outer circle -area of inner circle
=>Πr1^2-Πr2^2
=>Π(r1^2-r2^2)
=>22/7(14×14-21/2×21/2)
=>22/7×343/4
=>269.5cm

Answer 2

$\sf\purple{Circumference\:of\:outer\:circle-Circumference\:of}$

$\sf\purple{inner\:circle}$

$\longrightarrow$$\sf{(88-66)cm}$

$\longrightarrow$$\sf{2π(r1-r2)=22cm}$

$\sf\purple{Hence,the\:width \: of \: the\: ring\: is }$

$\longrightarrow$$\sf{r1-r2=\frac{22}{2π}}$

$\longrightarrow$$\sf{\frac{22×7}{2×22}}$

$\longrightarrow$${\boxed{\sf{3.5cm}}}$