how do you find the answer to a=bc if you were rearranging formulas

If you know b and c multiply them

If you know a and b, divide a by b

If you know a and c, divide a by c

An easy way to visualize this is with a triangle, a would be at the top and b/c at the bottom, to use it multiply across and divide going down, Google formula triangle to get a better view of it