If you know the area and perimeter of a rectangle, you can figure out the length and width. STILL don't believe us?Just watch. Practice this lesson yourself on KhanAcademy.org right now: https://www.khanacademy.org/math/cc-fourth-grade-math/cc-4th-measurement-topic/cc-4th-area-and-perimeter/e/area_of_squares_and_rectangles?utm_source=YT&utm_medium=Desc&utm_campaign=4thgrade Watch the next lesson: https://www.khanacademy.org/math/cc-fourth-grade-math/cc-4th-measurement-topic/cc-4th-area-and-perimeter/v/comparing-area?utm_source=YT&utm_medium=Desc&utm_campaign=4thgrade Missed the previous lesson? https://www.khanacademy.org/math/cc-fourth-grade-math/cc-4th-measurement-topic/cc-4th-area-and-perimeter/v/width-from-perimeter?utm_source=YT&utm_medium=Desc&utm_campaign=4thgrade Grade 4th on Khan Academy: 4th grade is the time to start really fine-tuning your arithmetic skills. Not only will you be a multi-digit addition and subtraction rockstar, but you'll extend the multiplication and division that you started in 3rd grade to several digits. You'll also discover that you sometimes have something left over (called a "remainder") when you divide. In 3rd grade you learned what a fraction is. Now you'll start adding, subtracting, multiplying, and comparing them. You'll also see how they relate to decimals. On other fronts, you'll learn how to convert between different units (which is super important when comparing the size and speed of robot unicorns in different countries) and continue your journey thinking about various shapes in two dimensions. Some of the foundational concepts of geometry (like lines, rays and angles) also get introduced. As always, we'll round this out with a healthy dose of applied word problems and explorations of number patterns and properties (including the ideas of factors, multiples and prime numbers). The fun must not stop! (Content was selected for this grade level based on a typical curriculum in the United States.) ... https://www.youtube.com/watch?v=-J-6VGxld54 Note: All Khan Academy content is available for free at (www.khanacademy.org)

This video demonstrates how different points of the business cycle correspond to the production possibilities curve. The discussion includes unemployment, inflation, expansions, recessions and economic growth. Practice this yourself on Khan Academy right now: https://www.khanacademy.org/economics-finance-domain/ap-macroeconomics/economic-iondicators-and-the-business-cycle/business-cycles/e/the-business-cycle--gdp-and-unemployment Watch the next lesson: https://www.khanacademy.org/economics-finance-domain/ap-macroeconomics/national-income-and-price-determinations/aggregate-demand-ap/v/aggregate-demand Missed the previous lesson? Watch here: https://www.khanacademy.org/economics-finance-domain/ap-macroeconomics/economic-iondicators-and-the-business-cycle/business-cycles/v/the-business-cycle AP(R) Macroeconomics on Khan Academy: Macroeconomics is all about how an entire nation’s performance is determined and improved over time. Learn how factors like unemployment, inflation, interest rates, economic growth and recession are caused and how they affect individuals and society as a whole. We hit the traditional topics from an AP Macroeconomics course, including basic economic concepts, economic indicators, and the business cycle, national income and price determination, the financial sector, the long-run consequences of stabilization policies, and international trade and finance. ... https://www.youtube.com/watch?v=0F6lRMI_rHQ Note: All Khan Academy content is available for free at (www.khanacademy.org)