Distance formula review | Analytic geometry (article) | Khan Academy (2024)

Review the distance formula and how to apply it to solve problems.

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  • 17017

    6 years agoPosted 6 years ago. Direct link to 17017's post “The soccer field question...”

    The soccer field question confuses me - I don't understand how =√52 becomes 2√​13!
    Any help?

    (40 votes)

    • Ian Pulizzotto

      6 years agoPosted 6 years ago. Direct link to Ian Pulizzotto's post “To simplify √52, we look ...”

      Distance formula review | Analytic geometry (article) | Khan Academy (4)

      Distance formula review | Analytic geometry (article) | Khan Academy (5)

      Distance formula review | Analytic geometry (article) | Khan Academy (6)

      To simplify √52, we look for the largest perfect square factor of 52. This factor is 4.
      Since the square root of a product of positive numbers is the product of their square roots,
      √52 = √(4*13) =√4 * √13 = 2√13.

      (116 votes)

  • kristofer

    7 years agoPosted 7 years ago. Direct link to kristofer's post “what is the Pythagorean t...”

    what is the Pythagorean therom

    (6 votes)

  • Remedy

    a year agoPosted a year ago. Direct link to Remedy's post “I have a question about t...”

    I have a question about the last problem. Simplify one of the distances and the final formula is 2√13 + √13, but I didn't know the same number of square roots can be combined. Does anyone know where I can learn about it?

    (4 votes)

    • David Severin

      a year agoPosted a year ago. Direct link to David Severin's post “anytime you can substitut...”

      Distance formula review | Analytic geometry (article) | Khan Academy (14)

      anytime you can substitute an x, you may be able to simplify. Let x=√13, this gives 2x + x, and hopefully you understand by now that you can combine like terns to get 3x. Substitutin back in, you get 3√13.

      (10 votes)

  • Quinn Hays

    2 years agoPosted 2 years ago. Direct link to Quinn Hays's post “Am I allowed to use trigo...”

    Am I allowed to use trigonometry to solve these?

    (1 vote)

    • David Severin

      2 years agoPosted 2 years ago. Direct link to David Severin's post “If you use trig, it will ...”

      Distance formula review | Analytic geometry (article) | Khan Academy (18)

      If you use trig, it will be a more indirect way to get the answer, but you can if you want. You would have to find the inverse tan to find the angle, then apply either sin or cos to find the third side.

      (12 votes)

  • 349933

    4 years agoPosted 4 years ago. Direct link to 349933's post “Dont understand the graph”

    Dont understand the graph

    (5 votes)

    • BraedenHill001

      4 years agoPosted 4 years ago. Direct link to BraedenHill001's post “The graph is showing the ...”

      The graph is showing the x and y coordinates of the three points so that you can find the differences in x and y. Once you have found the difference in x and y, you can then solve using the Pythagorean Theorem.

      (3 votes)

  • Mateo Bump

    2 years agoPosted 2 years ago. Direct link to Mateo Bump's post “Hello, I Don't understand...”

    Hello, I Don't understand the distance between(2,2) and (4,7) I'm very confused and i'm good at math but wow.
    Any help?

    (0 votes)

    • Jerry Nilsson

      2 years agoPosted 2 years ago. Direct link to Jerry Nilsson's post “The two points are (𝑥₁, ...”

      Distance formula review | Analytic geometry (article) | Khan Academy (25)

      The two points are (𝑥₁, 𝑦₁) = (2, 2) and (𝑥₂, 𝑦₂) = (4, 7)

      The distance formula tells us
      𝑑 = √((𝑥₁ − 𝑥₂)² + (𝑦₁ − 𝑦₂)²)
      = √((2 − 4)² + (2 − 7)²)
      = √((−2)² + (−5)²)
      = √(4 + 25)
      = √29

      (13 votes)

  • kpop0215

    9 months agoPosted 9 months ago. Direct link to kpop0215's post “Why is the exponent at th...”

    Why is the exponent at the bottom?

    (3 votes)

    • Bani Hundal

      9 months agoPosted 9 months ago. Direct link to Bani Hundal's post “This is not an exponent, ...”

      This is not an exponent, it just shows the order.

      (6 votes)

  • Dayton

    7 months agoPosted 7 months ago. Direct link to Dayton's post “I find it so funny that t...”

    I find it so funny that the khan comments are so harmonic.

    (5 votes)

  • eva stepherson

    4 years agoPosted 4 years ago. Direct link to eva stepherson's post “It all confuses me. But m...”

    It all confuses me. But mostly the soccer feild.

    (5 votes)

  • XxGl1tchxX

    9 months agoPosted 9 months ago. Direct link to XxGl1tchxX's post “Are there any quick and e...”

    Are there any quick and easy ways to remember the Distance Formula? It's so long! I find it very hard to remember!!

    (2 votes)

    • Ian Pulizzotto

      9 months agoPosted 9 months ago. Direct link to Ian Pulizzotto's post “The distance formula is e...”

      The distance formula is easier to remember if you observe that it comes from the Pythagorean theorem.

      Imagine a right triangle with vertices at (x_1, y_1), (x_2, y_1), and (x_2, y_2). The legs have lengths |x_2 - x_1| and |y_2 - y_1|, and the hypotenuse is the distance between (x_1, y_1) and (x_2, y_2). The distance formula then follows from using the Pythagorean theorem on this right triangle.

      Have a blessed, wonderful day!

      (5 votes)

Distance formula review | Analytic geometry (article) | Khan Academy (2024)

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