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Get ready for Algebra 2

Course: Get ready for Algebra 2>Unit 5

Lesson 1: Pythagorean theorem

Pythagorean theorem intro problems

Practice using the Pythagorean theorem to solve for missing side lengths on right triangles.  Each question is slightly more challenging than the previous.

Pythagorean theorem

The equation for the Pythagorean theorem is
a, squared, plus, b, squared, equals, c, squared
where a and b are the lengths of the two legs of the triangle, and c is the length of the hypotenuse.
Want to learn more about the Pythagorean theorem? Check out this video.

Practice problems

Problem 1
• Current
Find the value of x in the triangle shown below.
Choose 1 answer:

Want more Pythagorean theorem practice? Check out this exercise.

Want to join the conversation?

• Is there any way on how to do Pythagorean theorem easier im having trouble understanding
(47 votes)
• You can remember easy "Pythagorean Triples" like the famous 3-4-5 combo, with 5 being the hypotenuse. There are also some other not-as-famous triples like the 5-12-13 triple, the 7-24-25 triple, and the 9-40-41. Note that the hypotenuse of these "triples" is always the largest number.
(10 votes)
• there is so much history in the comments
(37 votes)
• this was disrespectful
(1 vote)
• i wonder how we figured out the pythagoream theorem
(26 votes)
• It was proven by Pythagoras. There are several popular proofs (even one done by a former US president [Garfield]). Look up proof of Pythagoras Theorem on YouTube.
(7 votes)
• Just a quick question, so in a test it could say find the distance of the other 2 sides of the triangle. Can you find out the other 2 sides using the pythagorean theorem or is there another way to find that out?
(13 votes)
• There is no way to do it if you are only given 1 side :(
(8 votes)
• So, for the Pythagorean Theorem you do a squared plus b squared equals c squared. Why is a+c=b a thing? I don't get it.
(0 votes)
• a+c cannot equal b. This is because c is the hypotenuse. Instead, you could do c²-a²=b².
(39 votes)
• when am I going to use this in life?
(11 votes)
• You won’t
(6 votes)
• how can i find the b (the one one the side thats straight)
(7 votes)
• you would instead do c^2-a^2=b^2. if you are missing "a" you can also swap those and do c^2 - b^2 = a^2
(5 votes)
• I don't exactly understand how to do this, is there an easier way to do this?
(10 votes)
• Why do people always ask obvious questions and then get a ton of votes?!
(10 votes)
• because it is easier to full around
(1 vote)
• is there a better way to learn this?
(10 votes)