3. For this one, we know that the sum of the angles is equal to 115 and we have the measure of one angle. So, we will subtract the one angle from the total to get the measure of the second angle. 115-90=25
4. We will do the same for this one as we did in number 3. The sum of the angles is 70, and one of the angles is 40. 70-40=30
5. Lets add the two angles up first. 45+45=90. Two angles that add up to 90 are complementary angles.