Area and perimeter word problem: width of a dog pen | Khan Academy

If you know the perimeter and the length of a rectangle, you can figure out the width. Don't believe us? Watch and become a believer.

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.)

About Khan Academy: Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. We tackle math, science, computer programming, history, art history, economics, and more. Our math missions guide learners from kindergarten to calculus using state-of-the-art, adaptive technology that identifies strengths and learning gaps. We've also partnered with institutions like NASA, The Museum of Modern Art, The California Academy of Sciences, and MIT to offer specialized content.

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[lisagwin]

This really helps me in school because when I’m Confused I go to a video on this website

[ToTCaMbIu]

1:20 it should be 78 ft not 28 please correct it. 

[wolfyboy]

This good for me because I don’t need to spend another week on area and perimeter and get to geometry 📐 (I’m in fourth grade)

[loretaadam]

What are the relationship of the rectangle

[CJ_Dimmer]

Why would a dog pen be that big though-

[malcolmenmedio]

Alch tengo que hacer una tarea no me acordaré de este comentario asi que si lo ves recuérdame que comente aquí

[brando_faul]

need hlp sad *crying* *snif* bye it so hard

[brando_faul]

i am playing pokemon go and my house is a pokemon gym and the onwer is me

[gracieg]

5 comments? Really? Us procrastinators who watch this just cause we want to can do better than that! Yup.That was weird.