Area & Perimeter

Perimeter

What is perimeter?

• Perimeter represents the total distance around the exterior of a 2D shape.
• To calculate perimeter, add together the lengths of all the sides.
• For a circle, the perimeter is referred to as the circumference.

How do I find the perimeter of a 2D shape?

• To find the perimeter of any 2D polygon, add the lengths of its sides.
• For any regular 2D shape, the perimeter equals the number of sides multiplied by the length of one side.
  • For example, a square with side length x cm has a perimeter of 4x cm.
• When dealing with more complex 2D shapes, use the given information to determine the lengths of some sides.
  • Shapes composed of two or more 2D shapes are called compound shapes.
• In compound shapes made of two rectangles (e.g., an L-shape), the lengths of two shorter sides opposite a longer side will add up to the same length as the longer side.
  • For compound shapes made of different 2D shapes, additional information is needed to find the lengths of the sides.
  • Be familiar with the properties of 2D shapes to identify equal sides.
  • Equal sides might be marked with dashes or specified in the question, such as in rectangles, parallelograms, or isosceles triangles.

Area Formulae

What is area and why do we need to calculate it?

• Area refers to the space occupied by a two-dimensional shape. It is crucial in various practical scenarios, guiding us in determining space requirements for designs and constructions.
• Volume pertains to the capacity of three-dimensional shapes and their spatial dimensions, contrasting with area's focus on flat surfaces.
• Applications of area extend beyond mathematical realms, finding practical utility in everyday situations. For instance, calculating floor space for carpeting or land area for sports field layouts.

Area - Using Formulae

• Familiarize yourself with basic formulas and feel confident using them.
• Note that some area formulas involve distances that may not correspond to one of the shape's sides.
• Understand the meaning of the different letters in each formula.
• Master these fundamental formulas, as more complex ones will be provided during exams: