Please help me asap!

Which best explains why this triangle is or is not a right triangle?

Acar started driving from city a to city b, distance between which is 620 miles, at a rate of 60 mph. two hours later a truck left city b and started moving towards city a at a rate of 40 mph. what distance from city a is the point where the truck and the car will meet?

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.