What is the radius of this; it’s not the obvious 4 btw

What is the point-slope form of the equation for the line with a slope of -2 that passes through (1,4)?

Graph the line that represents a proportional relationship between d and t with the property that an increase of 33 units in t corresponds to an increase of 44 units in d. what is the unit rate of change of dd with respect to t? (that is, a change of 11 unit in t will correspond to a change of how many units in d? )

In the diagram, ab is tangent to c, ab = 4 inches, and ad = 2 inches. find the radius of the circle.