Volume in unit cubes by decomposing shape | Measurement and data | 5th grade | Khan Academy

TL;DR

The video explains how to find the volume of a figure in terms of unit cubes, using various methods.

Transcript

• [Voiceover] So these are two pictures of the same figure. This is a front view of the object, and this is the back view of the object. And if a unit cube looks like this, what I want to do is I want to figure out the volume of this figure in terms of unit cubes, or in terms of cubic units. I encourage you to pause the video and think of it on you... Read More

Key Insights

• 🔇 The volume of a figure can be found by breaking it down into smaller shapes and finding their individual volumes.
• 🔇 The volume of a shape is calculated by multiplying its length, width, and height.
• 🔇 The total volume of a figure is the sum of the volumes of its individual parts.

Questions & Answers

Q: How can we find the volume of the yellow part of the figure?

To find the volume of the yellow part, we multiply its length, width, and height, which are 4 units, 4 units, and 2 units, respectively. So, the volume is 4 x 4 x 2 = 32 cubic units.

Q: What are the dimensions and volume of the other piece in the figure?

The other piece has dimensions of 2 units wide, 2 units high, and 1 unit deep. Its volume is calculated by multiplying these dimensions, which gives us 4 cubic units.

Q: How can we find the total volume of the figure?

The total volume is the sum of the volumes of the yellow part and the other piece. So, 32 + 32 + 4 = 36 cubic units.

Q: Is there another method to find the total volume?

Yes, another method is to find the volume of the blue layer, which is one unit deep, and then double it. Counting the cubes in the blue layer gives us 18 cubes. Therefore, the total volume is 18 + 18 = 36 cubic units.

Summary & Key Takeaways

• The video shows two pictures of the same figure, a front view, and a back view, and explains how to find its volume in terms of unit cubes.

• One method is to break the figure into a rectangular prism, find the volume of each part, and add them together.

• Another method is to find the volume of the blue layer and double it, as the red layer has the same volume.