The blank spaces in the task content can be filled with; Substitution property, 90° and subtraction property.
<h3>What are the missing statements in the proof?</h3>
Since it follows from the vertical angles theorem that angle 1 = angle 4 as they are congruent.
Additionally, angles 1 and 2 are said to be complementary and hence, the sum of their measures is equal to 90°.
Finally, by virtue of the subtraction property of equality, the measure of angle 2 is; 90° - 40° = 50°.
Read more on complementary angles;
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