The sum of the areas of two circles which touch each other externally is 153π, If the sum of their radii is 15, find the ratio of the larger to the smaller radius
Correct Answer : A
The resistance of a wire is proportional to its length and inversely proportional to the square of its radius. Two wires of the same material have the same resistance and their radii are in the ratio 9 : 8. If the length of the first wire is 162 cms., find the length of the other.
If a, b and c are three real numbers, then which of the following is not true?
On a semicircle with diameter AD, chord BC is parallel to the diameter. Further, each of the chords AB and CD has length 2, while AD has length 8. What is the length of BC?