Square: Area = side × side
Rectangle: Area = length × width
Triangle: Area = 1/2 × base × height
Circle: Area = π × radius × radius
Parallelogram: Area = base × height
Trapezoid: Area = 1/2 × (sum of parallel sides) × height
Rhombus: Area = 1/2 × diagonal 1 × diagonal 2
Irregular shape: Divide into simpler shapes, calculate each area, then add them together