1.Find the equation of the circle (in standard form) if the center is (2,-3) and radius is 4 units.

2.Find the equation of the circle (in standard form) if the center is (1,-3) and passing through the point(4,1).

3. The diameter of a circle is 18 units and its center is at (-3,8). what is the equation of the circle ( in general form)

4. What figure is formed when the pointsA(3,7), B (11,10) ,C(11,5) And D (3,2) are connected consecutively? illustrate your answer.​