Load cell series connection
You have two options:
As K H said, you can use MA of 4:1 to allow you to weigh the weight, bare in mind that any higher than 200KG you will get bad results. This could be done with levers and a fulcrum. Also consider platform weight.

OR

You could use four load sensors at the corners, then take the inputs form each into a microcontroller, find the average, multiply by four, and use that. Again, account for platform weight.