Paralellogram's area would be A = bh (or base times height)
Rectangle or square would be A = lw (length times width)
Triangle would be A = 1/2 bh (basically divide the base x height by 2)
Trapezoid would be A = 1/2 (a+b)h (or for me I do base 1 which is a and base 2 which is b times height and then divide by 2 or division then multiplication first)