Count how many times the mark lands within the circle, and how many times the mark lands outside the circle, but still within the frame of the rectangle.
Let A1 be the first approximation to the area of the circle.
Compare the A1 which has been calculated above to Acircle.
Run the program again and decide A2, which is the next approximation to the area of the circle, there are now 50 marks in total on the wall (not all of them will be inside the frames of the rectangle)
Compare the A2, which has been calculated above, to Acircle.
Now calculate the corresponding A3 and A4 for when there are respectively 75 and 100 marks on the wall.
You should now be able to decide the sequence of A1,A2, A3, A4… They are nearing Acircle, this is the process of converging.
Now draw a funny figure on a rectangle. Use a piece of A4 paper or a piece of carton.
By using the method above, decide the area of this funny figure.
If you want an answer to compare to, you can weigh the rectangle then cut out the funny figure and weigh that too.
You will now be able to use the formula