The inner and outer radii of two concentric circles are 6.7 cm and 9.5 cm, respectively. Whatis the difference between their circumferences (in cm)? Take $\pi =\frac{22}{7}$
Answer & explanation
Correct answer: option 4
Given,
Inner radius of concentric circles = 6.7cm
Outer radius of concentric circles = 9.5 cm
We know that,
Circumference of circle = 2πr
Circumference of small circle = 2 × π × 6.7 = 13.4π
Circumference of big circle = 2 × π × 9.5 = 19π
Difference between their circumference = (19 - 13.4)π = 5.6 × \(\frac{22}{7}\)= 17.6 cm