Geometrymedium · Past Paper
If two circles of radii 18 cm and 8 cm touch each other externally, find the length of their direct common tangent.
A10 cm
B24 cm
C26 cm
D14 cm
✓ Correct Answer: B — 24 cm
Length = sqrt(d^2 - (r1-r2)^2). d = 18+8=26. L = sqrt(26^2 - 10^2) = sqrt(676-100) = sqrt(576) = 24 cm.
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