To figure the area of a square or rectangle, measure the Length & Width and multiply.
Length x Width = Area
To calculate the area of a trapezoid, add the two lengths together and divide by 2. Then take that number and multiply it by the width.
ie: Length A + Length B / 2 x Width = Area
To calculate the area of a right triangle, multiply the two sides that contact the right angle and divide by 2.
ie: Base x Height / 2 = Area
To calculate the area of a circle, take the radius times the radius, then multiply by 3.14. Radius is a straight line from the center of a circle to the outside of the circle.
(Radius x Radius) x 3.14 = Area
Half Circle divide by 2
(Radius x Radius) x 3.14 / 2 = Area
Quarter Circle divide by 4
(Radius x Radius) x 3.14 / 4 = Area