Area of Plane Shapes

	Triangle Area = ½ × b × h b = base h = vertical height			Square Area = a2 a = length of side
	Rectangle Area = w × h w = width h = height			Parallelogram Area = b × h b = base h = vertical height
	Trapezoid (US) Trapezium (UK) Area = ½(a+b) × h h = vertical height			Circle Area = π × r2 Circumference = 2 × π × r r = radius
	Ellipse Area = πab			Sector Area = ½ × r2 × θ r = radius θ = angle in radians