4.2. Exterior Angles Theorems http://www.ck12.org
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- Suppose the measures of the three angles of a triangle are x, y, and z. Explain whyx+y+z=180.
- 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. - 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.