Answer:
135 cubic inches.
Step-by-step explanation:
Given : The ratio of the base edges of two similar pyramids is 3:4
The volume of the larger pyramid is 320 cubic inches.
To Find: What is the volume of the smaller pyramid?
Solution:
The ratio of the base edges of two similar pyramids is 3:4
The volume of the larger pyramid is 320 cubic inches.
The ratio of the volume of pyramids is equal to the ratio of the cubes of the sides of pyramids .
So, 



Thus the volume of smaller pyramid is 135 cubic inches.