This lesson transitions students from thinking about the area of two-dimensional figures with fractional linear measurements to reasoning about the volume of prisms with fractional edge lengths.

Students begin by solving problems about triangles. They find the area of a triangle given a pair of base and corresponding height measurements. They also calculate an unknown base or height given the other two measurements.

Next, students explore the volume of rectangular prisms whose edge lengths are not whole numbers. In grade 5, students determined the volume of a rectangular prism by finding the number of unit cubes that can be packed into the prism without gaps or overlaps. They concluded that this number is equal to the product of the edge lengths. Here, students encounter a prism whose edge lengths are multiples of inch. They find its volume by packing it with -inch cubes, quantifying the number of cubes, and multiplying it by , the volume of a single cube in cubic inches.

By repeating this reasoning and noticing regularity (MP8), students see that the volume of a rectangular prism with fractional edge lengths can also be found by multiplying its edge lengths directly.