Choose the correct condition when two circles touch each other externally ______?

r1 × r2 = C1C2

r1 + r2 = C1C2

r1 - r2 = C1C2

None of these

When two circles touch each other externally, they have a single point of contact.

The distance between their centers (C1C2) is equal to the sum of their radii (r1 + r2).