Help meee please.,.

How can you construct perpendicular lines and prove theorems about perpendicular lines

Using pert, adam munson was able to determine that the expected project completion time for the construction of a pleasure yacht is 21 months, and the project variance is 4. a) what is the probability that the project will be completed in 17 months? b) what is the probability that the project will be completed in 20 months? c) what is the probability that the project will be completed in 23 months? d) what is the probability that the project will be completed in 25 months? e) what is the due date that yields a 95% chance of completion?

Which of these angles are complementary? a. 45o and 45o b. 63o and 117o c. 45o and 135o d. 90o and 45o