Two circles with radii of 6 cm and 3 cm have a distance of 15 cm between their centers. What is the length of the common internal tangent between the two circles?
Show answer & explanation
Correct answer: B
Explanation
Given:
r₁ = 6 cm
r₂ = 3 cm
Distance between centers d = 15 cm
Formula:
Length of internal common tangent = √[d² − (r₁ + r₂)²]
= √[15² − (6 + 3)²]
= √[225 − 9²]
= √[225 − 81]
= √144
= 12
Length of internal common tangent = 12 cm