I want to draw a sector with the angle on it. I have tried several tools but didn't find any easy way of doing it.
[Math] Software to draw easily sectors with angle on it
circlesgeometrymath-software
Related Solutions
Fix one side, say segment $AB$, then draw (one arc of) the circle $c$ which consists of those points from where $AB$ is seen in the given angle. So that the centre of the parallelogramma has to be on $c$. Then enlarge $c$ to its double from center $A$, getting arc of circle $c'$ which must contain a $3$rd vertex of the parallelogramma, so finally just draw the circle centered at $B$ with the length of the other side.
Although this is a late answer neverthless it may be useful for some other readers.
I would recommend Geogebra which is a dynamic mathematics software for learning and teaching mathematics. It is also open source software.
3D properties have been added to geogebra version 5. You can easily create 3D objects like pyramids, prisms, spheres, cylinders, cones ... or you can draw graphics of multivariable functions of the form $f(x,y)$ simply.
For example from View->3D Graphics
in command line, type $f(x,y)=x^2+y^2$
or type $y=-5 $ for plane graph
You can explore the rich properties of Geogebra in time.
Best Answer
You can use Geogebra, a free program that can be used to created all kinds of geometric images, including this one. First create a circle with center $C$ and point on the circle $P$. Then make an angle of $45^\circ$ from $AP$, to get $Q$ on the circle. Last, there is a function to select the circle-sector, but I don't know by heart which one.