From 20 miles to 11 miles (decrease) answer? ?

What two criteria are needed for triangles to be similar

The parabola x = y² - 9 opens: a.)up b.)down c.) right d.)left

The general form of the quetion of a circle is ax^2+by^2+cx+dy+e=0 where a=b=0 if the circle has a radius of three units and the center lies on the y axis which set of values of a, b, c, d, and e might correspond to the circle