CK-12 Geometry-Concepts

(Marvins-Underground-K-12) #1

4.2. Exterior Angles Theorems http://www.ck12.org



  1. What ism^61 +m^62 +m^6 3?

  2. What ism^64 +m^65 +m^6 6?

  3. What ism^67 +m^68 +m^6 9?


Solve forx.


10.


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12.



  1. Suppose the measures of the three angles of a triangle are x, y, and z. Explain whyx+y+z=180.

  2. Suppose the measures of the three angles of a triangle are x, y, and z. Explain why the expression( 180 −x)+
    ( 180 −y)+( 180 −z)represents the sum of the exterior angles of the triangle.

  3. Use your answers to the previous two problems to help justify why the sum of the exterior angles of a triangle is
    360 degrees. Hint: Use algebra to show that( 180 −x)+( 180 −y)+( 180 −z)must equal 360 ifx+y+z=180.

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