arc length = radius multiplied by angle in radians
radius = 7 angle = 90 degrees
90 degrees = 1.571 radians
7 × 1.571 = 10.997
AB is 10.997 or 11 inches long
Cannot be applied on a single factor.
Hope this helps.
Rays are named according to their endpoints, the first one named is the "starting" endpoint, the second one is the one that will continue on into infinity. Therefore, ray BA has a terminal endpoint at B and goes through point A into infinity. Ray AB has a terminal endpoint at A and goes through point B into infinity. Definitely NOT the same ray.
3y means *three times y.* So it can be written as 3y or 3•y or written out three times the variable y.