Answer:
1. 180
2. 101
Explanation:
Angle measures 4, 1, and 5 have to all equal to 180 degrees because they all form a straight line, a straight line totals to 180 degrees.
Therefore, by the angle addition property m∠4 + m∠1 + m∠5 = 180°
Given two angle measures (4 and 5), all we have to do in order to find angle measure 1 is subtract the total of the given measures from 180 degrees to find the unknown measure of angle 1.
Solve for the missing angle measure by setting up an equation:
∠4 + ∠5 + ∠1 = 180
Substitute given values in the appropriate angle measures:
49 + 30 + ∠1 = 180
Combine values:
79 + ∠1 = 180
Subtract 79 from both sides because the inverse operation of addition is subtraction:
-79 -79
m∠1 = 101°