Area enclosed by two concentric circles

The area enclosed between two concentric circles is 770 cm^(2) .If the radii of the circles differ by 7 cm ,find both the radii.

Find the area enclosed between two concentric circles of radii 3.5 cm and 7 cm. A third concentric circle is drawn outside the 7 cm circle, such that the area enclosed between it and the 7 cm circle is same as that between the two inner circles. Find the radius of the third circle correct to one decimal place.

In Fig. 12.69, find the area of the shaded region, enclosed between two concentric circles of rade 7 cm and 14 cm where angleAOC=40^(@) ("Use "pi=(22)/(7))

The area enclosed between the concentric circles is 770cm^(2). If the radius of the outer circle is 21cm, find the radius of the inner circle.

The area of circle whose radius is 6 cm is trisected by two concentric circles. The radius of the smallest circle is

The area of a circle whose radius is 6cm, is trisected by two concentric circles.Find the radius of the smallest circle.

The area enclosed between the circumferences of two concentric circles is 16picm^(2) and their radii are in the ratio 5 : 3. What is the area of the outer circle ?

The area enclosed by the circumference of two concentric circles is 423.5 cm^(2) . If the circumference of outer circle is 132 cm. Calculate the radius of the inner circle

A chord of the larger among two concentric circles is of length 10 cm and it is tangent to the smaller circle. What is the area (in cm ) of the annular portion between the two circles?