Divide a graph into half

How do I calculate the area of entire property here...do I need to use integration ?

And for the areas of lnkk' ?

Entire area: Calculate the area of the entire property including the part to the left of the arc.  Then calculate the area to the left of the arc and subtract it from the first area.
It's not really clear to me what's going on with M and N.  Is N on the line from M to A?

Do a similar area calculation for LNKK'.  That is, calculate the area as if the arc is a straight line, then calculate the area between the arc and that straight line, then subtract the second from the first.

NA is the arc

There is no line from M to A
That NA line is just a dashed line under the arc NA
It's like starting from A there are points B, C,......M,
Connecting with a straight line
At th last M connect s to N with a straight line
That's all

Got it.  That slightly complicates matters.
Now you have three areas to consider: NLM, the area between the NA arc and the NA dashed line, and the area to the right of the arc.

I have a slightly different approach to consider.  We'll set aside NLM as it will have to be dealt with separately.

Instead of drawing a line from each point to the arc as I described (coincident with a radius), draw the lines horizontally to the dashed line.  Alternatively, it may make for easier calculations if you draw the lines such that they hit the dashed line at 90 degrees.  Call the intersection with the arc as ' and intersection with the dashed line as ''.  You then have a four-sided polygon in each case.  For example, KK''J''J would have K' and J' as the crossing points between the arc and KK'' and JJ'' respectively.  It should be straightforward to calculate the area of the polygon as well as the area to the left of the arc.

So what I understand that you are suggesting is drop a perpendicular from each point to the dotted line.
And so we calculate the area of the polygon
and calculate the area of arc above the dashed line.
Subtracting that will give the desired area..

Sounds good..

Is it possible to draw this graph on some mathematical tool online etc some software just to verify the answers ?

Thanks

"Is it possible to draw this graph on some mathematical tool online etc some software just to verify the answers ? "
I have no clue.  You can do some rough checks by moving the points around to where it is a very simple polygon and confirm that it works properly there.  You could then make it more complicated (offset to one side) and confirm that it is still correct.  That doesn't prove it at all, but failure to work there shows that it's not right.