You know what the area of the four parts must be.

Think about symmetrical drawings.

Can you draw three lines inside the circle in such a way that they enclose an area which can be expanded or contracted to give the required area?

The Solution section gives one possibility (see link above). There are many other possibilities you could investigate.

Here is just one alternative line of approach you could pursue:

The diagram shows another solution for 3 lines but the same principle applies to any regular polygon. For an $n$-gon the angle marked at the centre of the circle $C$ will be ${\pi \over n}$. As $n$ gets larger the polygons will get smaller and the lines will 'radiate' out more like the spokes of a wheel.