Step 1. If you know Altitude (height) and side s the formula is area = height x s.
Step 2. If you know the length of one side s and the measure of one angle the formula is: area = s2 sin (<_ A) = s2 sin (<_B)
Step 3. If you know the lengths of the diagonals the formula is: area = (d1 x d2)2.
