The perimeter of a triangle with sides 3 cm, 4 cm and 5 cm is A12 cm B60 cm C7 cm D6 cm Tap an answer to check. Show the answer Answer: A. 12 cm Add all sides: 3 + 4 + 5 = 12 cm. Report a problem The answer is wrong Spelling or typing mistake The question is unclear Out of date Something else Send