2018 · Q73
The radii of two circles are 4.5 cm and 3.5 cm respectively. The distance between the centres of the circles is 10 cm. What is the length of the transverse common tangent?
Elementary MathematicsCircles
- A4 cm
- B5 cm
- C6 cm
- D7 cm
Explanation
For a transverse common tangent the radii add: length = √(d² − (r₁ + r₂)²) = √(100 − 64) = 6 cm, option (C). The trap is using (r₁ − r₂) for the direct tangent instead.