When finding area of a circle, do your square the radius first or multiple the radius with pi?

If the slope of one line equals the slope of another line then ? a) the two lines are intersecting lines b) the two lines are perpendicular lines c) the two lines are parallel lines d) the two lines always have very steep slopes

The longer leg of a 30° 60° 90° triangle is 16 times square root of three how long is a shorter leg

Which of the choices shown could be used to prove that aacp=abcp ?