If a quadrilateral has three angles measuring 60',45' and 100' what is the angle of the fourth angle

These question are hard can you me with answers

(hurry! ) which expression is equivalent to the following complex fraction?

Two cars which are 40 miles apart start moving simultaneously in the same direction with constant speeds. if the speed of the car which is behind is 56 mph and the speed of the other car is 48 mph, how many hours will it take for the car which is behind to catch up the car ahead of it?