An alternative parametrisation of the circle is. Radius is a radial line from the focus to any point of a curve. OK so you need the end date of a quarter instead of the start date or the number and for this the formula which we can use is.
X - a2 y - b2 r2 y - b2 r2 - x - a2 If its a quarter circle then y b and x a.
I pr 4 4. When making a half circle skirt use this formula. So you can find the area of the whole circle and then divide by 4 to find the area of your quarter circle. Displaystyle ybrsin t where t is a parametric variable in the range 0 to 2 p interpreted geometrically as the angle that the ray from a b to x y makes with the positive x -axis.