two concentric circles have radii 280m and 350m respectively.find the difference between their circumference

Two concentric circles are of radii 5cm and 3cm respectively. Find the length of the chord of the larger circle which touches the smaller circle.

Two concentric circles have radii 20 cm and 15 cm. Find the area of ring shaped region

The radii of two concentric circles are 5 cm and 3 cm respectively . Find the length of the chord of the greater circle which is also a tangent to the smaller circle.

If the circumferences of two concentric circles forming a ring are 88cm and 66cm respectively.Find the width of the ring.

The radii of two circles are 19 cm and 9 cm respectively. Find the radius of the circle which has circumference equal to the sum of the circumference of the two circles.

The radii of two circles are 19 cm and 9 cm respectively. Find the radius of the circle which has circumference equal to the sum of the circumferences of the two circles.

The circumferences of two circles are 132 metres and 176 metres respectively. What is the difference between the area of the larger circle and the smaller circle? (a) 1048 sq. m (b) 1076 sq. m (c) 1078 sq. m (d) 1090 sq. m (e) None of these