Mary takes a sightseeing tour on a helicopter that can fly 450 miles against 15 mph headwind in the same amount of time it can travel 558 miles with a 15 mph. Find the speed, in miles per hour, of the helicopter.

If value of cos330° is √3/2 then find tan165°.

Determine the standard form of the equation of the line that passes through (-2,0) and (8,-5)

Which statement explains how you could use coordinate geometry to prove the opposite sides of a quadrilateral are congruent? a. use the slope formula to prove the slopes of the opposite sides are the same. b. use the slope formula to prove the slopes of the opposite sides are opposite reciprocals. c. use the distance formula to prove the lengths of the opposite sides are the same. d. use the distance formula to prove the midpoints of the opposite sides are the same.