I have 1000m of fencing to make a paddock, there is a 1km wall in which I can build the paddock onto.

I have to find the length or area (I'm not sure what) of a square shaped paddock, a triangle shaped paddock and half a circle. The notes I was given with them are -
Square - L=1000/3 to the power of 2 = 333 1/3
A= (333 1/3) to the power of 2

Triangle - Area = 1/2 ABsinC
C = 90 degrees
AB = 500
A = 490
B = 510

Half the circle - Pie R squared /2
R = (1000/pie)