Answer:
-20 + 3m + 6k
Step-by-step explanation:
Given,
Sides of the triangle = (5k-7) cm, (k-4) cm and (3m - 9) cm
Therefore,
Perimeter of the triangle in cm = (5k -7) cm + (k-4) cm + (3m - 9) cm
= 5k - 7 + k - 4 + 3m - 9
= 5k + k -7 - 4 - 9 + 3m
= 6k -20 + 3m
= - 20 + 3m + 6k
Hence,
-20 + 3m + 6k is the perimeter of the triangle in cm.
