Why isn't a vertical line a function? What test rules it out?

Kayla wants to find the width, ab, of a river. she walks along the edge of the river 65 ft and marks point c. then she walks 25 ft further and marks point d. she turns 90° and walks until her location, point a, and point c are collinear. she marks point e at this location, as shown. (a) can kayla conclude that δ and δ are similar? why or why not? (b) suppose de = 15 ft. what can kayla conclude about the width of the river?

The graph below shows the height of a projectile t seconds after it is launched. if acceleration due to gravity is -16 ft/s2, which equation models the height of the projectile correctly?

Select the number of ways in which a line and a circle can intersect