Find the area of the semicircle. Round your answer to the nearest hundredth. Please help!

Which of the following can be used to explain a statement in a geometric proof?

Alex took his brother to a birthday party. the party was scheduled to last for 1 and 3/4 hours but they stayed for 4/5 of an hour more. how long did she stay at the party?

Complex numbers multiply √-4 * √-25 and show all intermediate steps. alternative notation is sqrt(-4) * sqrt(-25).