The standard form equation for a circle is

where (h, k) is the center and r is the radius.
The standard form equation for an ellipse is

(center h, k and major and minor axes a and b)
This equation is standard form for neither, but might be general form for one.
The fourth one. If you were to fold it in, it would be that exact shape.
Answer:
47
Step-by-step explanation:
www.alcula.com/calculators/statistics/median/