Question

5. The diameter of a wheel is 0.70 m. Find the distance covered by it in 500 revolution.if the
wheel takes 5 minutes to make 500 revolutions, find its speed in (a) m/s and (b) km\h.
7. The ratio of the radii of two circles is 8:15. Find the ratio of their circumferences.
.8. Of the two concentric circles, t circumference of the outer circle is 132 cm and the circumference
of the inner circle is 88 cm. Find the difference between their radii.
9. The radii of two circles are 77 cm and 91 cm respectively. How much more is the circumference
of the second circle than the first?
10.The diameter of a wheel of a cycle is 70 cm. The wheel moves slowly along a road. How far wil
it go in 24 complete revolutions?​

Answer 1

Answer:

Step-by-step explanation: The ratio of the radii of two circles is 8:15. Find the ratio of their circumferences.

let r1 = 8x and r2 = 15x

then, circumference of two circle ratio : 2πr1/2πr2

                                                                 ⇒ 2π×8x/2π×15x

                                                                ⇒8:15

agar radii ka ratio diya ho to circumference ka ratio bhi wahi hoga

agar circumference ka ratio diya ho to radii ka ratio bhi wahi hoga