Perimeter and Area Formulas

 Perimeter is the distance around an object. It is easily the simplest formula. Simply add up all the sides of the shape, and you have your perimeter.  P = Add up all the sides P= Add up all sides P = P = 14cm

 The one exception is a circle. Since a circle has no sides really, there is a different formula to calculate the perimeter of a circle (also known as circumference). Multiply the radius by 2, and then by pi, to get the circumference.  C = 2 π r C = 2 π r C = 2 π 2 C = 4 π C = 12.57cm 2

 The formula for area varies with each shape.  Area is the amount of space within a 2D object.  Measured in units squared (u 2 )

 The area of a rectangle can be found by multiplying the length by the width.  A = l × w A = l × w A = 4 × 3 A = 12cm 2

 The area of a triangle can be found by multiplying the base by the height, and then dividing by two.  A = bh 2 A = bh /2 A = (6)(4)/2 A = 24/2 A = 12cm 2

 The area of a circle can be found by taking the radius, squaring it, and then multiplying by pi.  A = π r 2 A = π r 2 A = π 2 2 A = π 4 A= 12.57cm