Two circles of diameters 2 cm and 5.6 cm are such that the distance between their centers is 8.2 cm. What is the length of a common tangent to the circles that does not interest the line joining the centers?

Two circles of diameters 2 cm and 5.6 cm are such that the distance between their centers is 8.2 cm. What is the length of a common tangent to the circles that does not interest the line joining the centers? Correct Answer 8 cm

Formula used:

Length of a common tangent to the circles = √

where d = distance between the centres of the circle

and r1 and r2 are the radius of the circle

Calculation:

r1 = 1 cm

r2 = 5.6/2 = 2.8

Length of a common tangent to the circles = √ = √(8.2)2 - (1.8)2 = √(8.2 + 1.8)(8.2 - 1.8) = √(10 × 6.4) = 8 cm

Related Questions

The letters P, Q, R, S, T and U are to be placed one per vertex on a regular convex hexagon, but not necessarily in the same order. Consider the following statements: The line segment joining R and S is longer than the line segment joining P and Q. The line segment joining R and S is perpendicular to the line segment joining P and Q. The line segment joining R and U is parallel to the line segment joining T and Q. Based on the above statements, which one of the following options is CORRECT?
The distance between the centres of two circles is 24 cm. If the radius of the two circles are 4 cm and 8 cm, then what is the sum of the lengths (in cm) of the direct common tangent and the transverse common tangent?