Multiple choice

Two circles of radii 2 cm and 8 cm touch each other externally. What is the length of the direct common tangent?

  1. 6 cm.

  2. 10 cm.

  3. 8 cm.

  4. 12 cm.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

For two circles with radii r1 = 2 cm and r2 = 8 cm touching externally, the direct common tangent length = √(d² - (r2 - r1)²) where d = r1 + r2 = 10 cm (distance between centers). Tangent = √(100 - 36) = √64 = 8 cm. This uses the property that the tangent is perpendicular to the radius at the point of contact.

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