Perimeter is one of the most common SEA math questions Perimeter means the total distance around a shape. You find it by adding all the sides. Perfect for fences, borders, outlines, and measurement problems. Most tested SEA formulas: • Perimeter = add all sides • Rectangle = 2 × (length width) • Triangle = side side side • Area of rectangle = length × width • Area of triangle = ½ × base × height • Area of square = side × side • Volume = length × width × height Teach this, save this, revise this.