CK-12 Geometry Concepts

(Elliott) #1

http://www.ck12.org Chapter 8. Right Triangle Trigonometry


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  1. If the legs of a right triangle are 10 and 24, then the hypotenuse is _____.

  2. If the sides of a rectangle are 12 and 15, then the diagonal is _____.

  3. If the legs of a right triangle arexandy, then the hypotenuse is ____.

  4. If the sides of a square are 9, then the diagonal is _____.


Determine if the following sets of numbers are Pythagorean Triples.



  1. 12, 35, 37

  2. 9, 17, 18

  3. 10, 15, 21

  4. 11, 60, 61

  5. 15, 20, 25

  6. 18, 73, 75


Pythagorean Theorem Proofs


The first proof below is similar to the one done earlier in this Concept. Use the picture below to answer the following
questions.



  1. Find the area of the square with sides(a+b).

  2. Find the sum of the areas of the square with sidescand the right triangles with legsaandb.

  3. The areas found in the previous two problems should be the same value. Set the expressions equal to each
    other and simplify to get the Pythagorean Theorem.


Major General James A. Garfield (and former President of the U.S) is credited with deriving this next proof of the
Pythagorean Theorem using a trapezoid.



  1. Find the area of the trapezoid using the trapezoid area formula:A=^12 (b 1 +b 2 )h

  2. Find the sum of the areas of the three right triangles in the diagram.

  3. The areas found in the previous two problems should be the same value. Set the expressions equal to each
    other and simplify to get the Pythagorean Theorem.

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