Find the area of a rectangle whose dimensions are

Find the area of a rectangle whose dimensions are 5  3 5 3

Find the area of a rectangle whose dimensions are 5  3 5 3

Find the area of a rectangle whose dimensions are 5  square units It takes 15 1x1 tiles to cover the rectangle.

Find the area of a rectangle whose dimensions are 5  3 5L5L 3 15 square units It takes 15 1x1 tiles to cover the rectangle. Area = Length x Width A = LW W

Find the perimeter of a rectangle whose dimensions are 5  3 5L5L 3W

Find the perimeter of a rectangle whose dimensions are 5  3 5L5L 3W “measure”

Find the perimeter of a rectangle whose dimensions are 5  3 5L5L 3W “around”

Find the perimeter of a rectangle whose dimensions are 5  3 5L5L 3W 5

Find the perimeter of a rectangle whose dimensions are 5  3 5L5L 3W 5 + 3

Find the perimeter of a rectangle whose dimensions are 5  3 5L5L 3W

Find the perimeter of a rectangle whose dimensions are 5  3 5L5L 3W

Find the perimeter of a rectangle whose dimensions are 5  3 5L5L 3 Perimeter = Length + Width + Length + Width P = 2L + 2W W

The DIAMETER is the measure across the circle

The DIAMETER is the measure across the circle through the center

The DIAMETER is the measure across the circle through the center The RADIUS is the measure from the center to any point on the circle The diameter = 2 times the radius d = 2r

Wrap the diameter around the circle

The diameter fits 3 times plus a little extra. The number  is the exact number of “diameters” needed to complete the circle.  is approximately 3.14

The diameter fits 3 times plus a little extra. The number  is the exact number of “diameters” needed to complete the circle.  is approximately 3.14 The measure around the circle (perimeter) is called the circumference.

The diameter fits 3 times plus a little extra. The number  is the exact number of “diameters” needed to complete the circle.  is approximately 3.14 The measure around the circle (perimeter) is called the circumference. The circumference =  times the diameter. C =  d

The are of a circle is the number of square units needed to fill the circle. The following formula gives the area of a circle: A =  r 2 example: A circle whose radius is 3 units has area 9   square units <a href = > Check the web page above to see a visual proof of the area formula

example:

The circumference of the circle is 10  What is the area of the shaded region?______

The circumference of the circle is 10  What is the area of the shaded region?______ C =  d d = 10 r = 5 10

The circumference of the circle is 10  What is the area of the shaded region?______ 10 the area of the square is 100

The circumference of the circle is 10  What is the area of the shaded region?______ 10 the area of the square is 100 the area of the circle is 25  - 5

The circumference of the circle is 10  What is the area of the shaded region?______ 10 the area of the square is 100 the area of the circle is 25  - 5 (100 – 25  ) square units  100 – 78.5 = 21.5 square units