Volume of rectangular pyramids using cubes | Grade 7 (TX TEKS) | Khan Academy

less than 1m read

·Nov 10, 2024

We'll be exploring the volumes of rectangular pyramids today with cubes and rectangular prisms. This is a cube; all the sides are the same length. To find the volume of a cube, I can multiply the length by the width by the height. For example, if the length of the cube is five and all sides are the same, then to find the volume I would do 5 * 5 * 5 = 125 cm cubed.

I can break this prism into three rectangular pyramids that are all congruent. So now we have a cube that's actually made out of three rectangular pyramids, and we can see here that all of the rectangular pyramids are congruent. The base of each rectangular pyramid is a square. The square is the same size as one face of our cube, and they all have the same height.

Since all of these rectangular pyramids are congruent, they all have the same volume. To summarize so far, three congruent pyramids can form a cube, and the volume of one of the pyramids will be 1/3 the volume of the entire cube. This is true for all cubes, but what about other rectangular prisms where the sides have different lengths?

15 Daily Rituals for Cultivating a Growth Mindset

How Electricity Actually Works

View All

Adding multi digit numbers with place value

What we’re going to do in this video is get some practice adding multiple digit numbers. But the point of it isn’t just to get the answer, but to understand why the method we use actually works. So we’re going to add 40,762 to 30,473, and you can pause t…

AP Microeconomics FRQ on perfect competition | AP(R) Microeconomics | Khan Academy

Is a type of question that you might see on an AP economics exam, and it’s talking about perfectly competitive markets. So it says a typical profit maximizing firm in a perfectly competitive constant cost industry is earning a positive economic profit. S…

Sound + Fire = Rubens' Tube

So Dr. Phil, uh, what’s going on here? Okay, what we’ve got here is a metal pipe with a whole lot of holes in it. We’re pumping gas through it, and we’ve lit it up, as you can see. So we have like a whole lot of, uh, buns and burners all in a row—a whole…

Worked free response question on unemployment | APⓇ Macroeconomics | Khan Academy

We are told the following table shows labor market data for country X, and they tell us how many are employed, frictionally unemployed, structurally unemployed, cyclically unemployed, and also not in the labor force. So this first question here, and actu…

This Is A Light-Nanosecond!

I trimmed my beard yesterday, so I’m feeling a bit like a baby today. But look at the trimmings! Specifically this one that is 2.4 fortnits worth of beard growth. How do I know? Well, because of this tool I made. This about 5 years ago to free people from…

Radians as ratio of arc length to radius | Circles | High school geometry | Khan Academy

What we’re going to do in this video is think about a way to measure angles. There’s several ways to do this. You might have seen this leveraging things like degrees in other videos, but now we’re going to introduce a new concept, or maybe you know this c…

Volume of rectangular pyramids using cubes | Grade 7 (TX TEKS) | Khan Academy

More Articles