Help Please! I know how to find a median, but I dont understand how to use variables. <3

Which math sentence can be used to determine if the triangle is a right triangle?

The equation of a circle is (x + 4)2 + (y + 6)2 = 16. determine the length of the radius. 10 4 16 8 my flower basket delivers flowers within a 20 mile radius of their store. if this area is represented graphically, with my flower basket located at (5, 2), what is the equation that represents the delivery area? (x - 2)2 + (y - 5)2 = 20 (x - 5)2 + (y - 2)2 = 20 (x + 5)2 + (y + 2)2 = 400 (x - 5)2 + (y - 2)2 = 400

The sum of the reciprocal of a positive number and the reciprocal of 2 more than the number is 3/4 equation: the number is