If we change the radius of a circle, how does the circumference and area change? Practice this lesson yourself on KhanAcademy.org right now: https://www.khanacademy.org/math/cc-seventh-grade-math/cc-7th-geometry/cc-7th-area-circumference/e/area-and-circumference-of-circles?utm_source=YT&utm_medium=Desc&utm_campaign=7thgrade Watch the next lesson: https://www.khanacademy.org/math/cc-seventh-grade-math/cc-7th-geometry/cc-7th-area-volume-surface-area/v/volume-of-gold-ring?utm_source=YT&utm_medium=Desc&utm_campaign=7thgrade Missed the previous lesson? https://www.khanacademy.org/math/cc-seventh-grade-math/cc-7th-geometry/cc-7th-area-circumference/v/area-of-shaded-region?utm_source=YT&utm_medium=Desc&utm_campaign=7thgrade Grade 7th on Khan Academy: 7th grade takes much of what you learned in 6th grade to an entirely new level. In particular, you'll now learn to do everything with negative numbers (we're talking everything--adding, subtracting, multiplying, dividing, fractions, decimals... everything!). You'll also take your algebraic skills to new heights by tackling two-step equations. 7th grade is also when you start thinking about probability (which is super important for realizing that casinos and lotteries are really just ways of taking money away from people who don't know probability) and dig deeper into the world of data and statistics. Onward! (Content was selected for this grade level based on a typical curriculum in the United States.) ... https://www.youtube.com/watch?v=GB9Rqsah2gs Note: All Khan Academy content is available for free at (www.khanacademy.org)

What is the volume of a jar of milk? How about a spoon? A swimming pool? Practice this lesson yourself on KhanAcademy.org right now: https://www.khanacademy.org/math/cc-third-grade-math/cc-third-grade-measurement/cc-third-grade-mass-volume/e/volume-word-problems-1?utm_source=YT&utm_medium=Desc&utm_campaign=3rdgrade Watch the next lesson: https://www.khanacademy.org/math/cc-third-grade-math/cc-third-grade-measurement/cc-third-grade-mass-volume/v/arithmetic-word-problems-with-volume?utm_source=YT&utm_medium=Desc&utm_campaign=3rdgrade Missed the previous lesson? https://www.khanacademy.org/math/cc-third-grade-math/cc-third-grade-measurement/cc-third-grade-mass-volume/v/mass-problems?utm_source=YT&utm_medium=Desc&utm_campaign=3rdgrade Grade 3rd on Khan Academy: We know you've been rocking through 2nd grade adding and subtracting all kinds of whole numbers (up to 2 digits, right?). That's awesome! In 3rd grade math we want you to start using bigger numbers and start multiplying and dividing, too. By the way, did you know that some numbers aren’t actually “whole?” They’re “partially whole.” We call them fractions! We want you to start playing around and having fun with those, too. There's also area, perimeter, and place value to be discovered. Whew. We have so much to do and can't wait to do it with you. Let's go! ... https://www.youtube.com/watch?v=mLRYCaYVWFc Note: All Khan Academy content is available for free at (www.khanacademy.org)