If pi=22/7 and you need to find the difference between the area of two different circles one having a radius of 21in and the other having a radius of 28 inches what would the difference be

Driving 75 mph, it takes alicia 2 hours to reach the airport to go on a vacation. it then takes her 4 hours to get to her destination with the jet traveling at a speed of 400 mph. how many miles does alicia travel to get to her destination?

Find the greatest common factor of the followig monomials 21u^5v,3u^4v^6, and 3u^2v^5

Ineed with angles and the measure of them i have abc a is 65 and b is (3x-10) and c is (2x) find the value of x