[" chord of one circle which is tangent to the other circle."],[" If the first three terms of an A.P are "b,c" and "2b," then find the ratio of "b" and "c.]

If the first three terms of an A.P. are b, c and 4b, then find the ratio of b and c.

If the first, second and the last terms of an A.P. are a,b,c respectively, then the sum of the A.P. is

If the first, second and the last terms of an A.P. are a,b,c respectively, then the sum of the A.P. is

The first term of an A.P. is the same as that of a G.P., the common difference of the one and the common ratio of the other are both 4. If the sum of the first three terms of each series are same, find the fourteenth term of each series.

In the following diagram four circles are tangent to every other circle. The radius of each of the circles A,B and C is 1. Find the radius of circle D, which is tangent to all the three given circles and lies at the centre.

In the following diagram there are three circles packed in another circle, such that each circle is tangent to all other circles in this arrangement. The radius of the circumscribing circle A is 1 cm, and circle B and circle C are congruent. Find the radius of the circle D.

In Fig. 10.74, C P and C Q are tangents to a circle with centre O . A R B is another tangent touching the circle at R . If C P=11 c m and B C=7c m , then find the length of B R . (FIGURE)

The first, second and last terms of an A.P. are a, b, c respectively, then the sum to first n terms is

If a,b,and c are three terms of an A.P such that a != b then (b-c)/(a-b) may be equal to

If a,b,and c are three terms of an A.P such that a != b then (b-c)/(a-b) may be equal to