All you have to do is find (3/10) of 60, and find the triangle with that number for its label.
The exact same kind of problem was answered correctly by 2 people for the question you posted 9 minutes earlier, and one of them even explained how he did it. If you're getting anything more than answers from Brainly ... I mean if you're actually getting HELP here ... then you ought to be able to answer this one on your own.
The question is asking three tenth of the actual figure, resulting in having to do 60 x 3/10= 180/10= 18. So, your answer us eighteen centimeters. I hope this helped u