Measurement of angle DEF would equal 180 because 71 plus 109 is 180
The answer is -1.5. Hope this helps
Step-by-step explanation:
Put the interior angle equal to 180.
It would look something like this:
x+45=180
-45 -45
180-45= 135 so the exterior angle would be 135!
According to the fundemintal counting princable the answer is 18.
