Ali has 18 meters of fence to enclose her garden and she wants this garden to have the greatest possible area. what should the dimensions of Ali's garden be

All you have to do is take 18 and divide it by four. That way when you do the parameter it will add up to 18. Next you find the area by taking the length of each side (4.5) so 4.5 * 4.5 and that is 20.25. This is the greatest area you will have. The dimensions of the garden should be 4.5 all around.