Use the formula
Area= base times height.
You're given that area =300cm^2 and base=20 cm.
Plug these into the equation to get 300=20 x height. Now, you just need to solve for height. To do this, you need to undo the multiplication of b x h by dividing the area by the base.
So, h = 300/20
Simplify for an answer of 15.
