Answer: Circumference of cake board is 35π cm.
Explanation:
Since we have given that
Diameter of a round cake = 30 cm
Diameter of a cake board is 5 cm longer than the diameter of a round cake.
So, Diameter of a cake board = 30+5=35 cm
So, radius of a cake board will be

As we know the formula for " Circumference of Circle ":
So, According to question, we get,

Hence, Circumference of cake board is 35π cm.