I've been stuck on this for about 2 hours but it still doesn't make any sense to me, please help

The measurement of one angle of a right triangle is 34°. what is the measurement of the third angle?

Jordan rides his bike 6 7/15 miles every day to deliver newspapers and to go to and from school. if his ride to and from school is 4 3/10 miles, how many miles is the trip to deliver newspapers? 1 1/3 1 1/6 2 1/6 2 4/5

What situation is an example of an observational study