Name________________________

EXTERIOR ANGLES OF A TRIANGLE  #1-KEY

Directions:  Find the measurement of each missing angle in the triangles below.  Remember, the Exterior Angles Theorem states that the exterior angle is congruent to the sum of the two non-adjacent angles.  For example, in Problem 1, the exterior angle (x) is congruent to the sum of the two angles furthest away (60̊ & 80̊).  			  

55̊

x

65̊

60̊

1)              	         	                2)                                              3)                                          4)  

80̊

50̊

18̊

40̊

x

x

60̊

40̊

112̊

x

50̊

   x = _140̊___             	                   x = __68̊___      		   x = _125̊___       	               x = _140̊___                 

15̊

x

40̊

x

52̊

137̊

37̊

5)                                           6)                                             7)                                           8)  

46̊

44̊

97̊

x

84̊

28̊

x

68̊

72̊

   x = __143̊__             	                   x = _112̊___      		   x = __43̊___       	               x = _136̊___                 

x

x

45̊

45̊

x

73̊

65̊

9)              	         	               10)                                              11)                                          12)  

25̊

 

125̊

x

57.5̊

45̊

70̊

49.5̊

30̊

   x = _135̊___             	                   x = _155̊___      		   x = _135̊___       	               x = 107̊___                 

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