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Facts about Area of Shapes. Dr. Kent Bryant 5/2011. SQUARE. L. L. IF A SQUARE HAS SIDES WITH LENGTH L THEN AREA = L X L EG. WHAT IS THE AREA OF A SQUARE WITH LENGTH 20 cm? Area = 20 cm X 20 cm = 400 cm2. RECTANGLE. W. L. IF A RECTANGLE HAS LENGTH L AND WIDTH W A = L X W
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Facts about Area of Shapes Dr. Kent Bryant 5/2011
SQUARE L L IF A SQUARE HAS SIDES WITH LENGTH L THEN AREA = L X L EG. WHAT IS THE AREA OF A SQUARE WITH LENGTH 20 cm? Area = 20 cm X 20 cm = 400 cm2
RECTANGLE W L IF A RECTANGLE HAS LENGTH L AND WIDTH W A = L X W EG. WHAT IS THE AREA OF A RECTANGLE WITH LENGTH 20cm AND WIDTH 40cm? Area =20 cm x 40 cm = 800 cm2
Triangle H B IF A TRIANGLE HAS HEIGHT H AND BASE B AREA = ½ B X H EG. WHAT IS THE AREA OF A TRIANGLE WITH HEIGHT 20 cm AND BASE 15 cm? Area = ½ x 20 x 15 – 150 cm2
Circumference of a Circle The diameter of a circle is the distance across the circle through the center point. The radius of a circle is the distance from the center to the outer edge of the circle. Diameter = 2 X radius The circumference of a circle is the distance around the circle Circumference = Diameter X π (C = π d) π = 3.14 Circumference = 2πr (r = radius) What is the circumference of a circle with radius 5 cm? C = 2πr = 2 X 3.14 X 5 = 31.4 cm
Area of a Circle R If a circle has a radius R then Area = π R2 Eg. What is the area of a circle with radius 10 cm? Area = 3.14 X 10 X 10 = 314 cm2
Area of Parallelogram B H B If a Parallelogram has height H and a base length of B then Area -= B X H Eg. What is the area of a Parallelogram with Height 10 cm and Base length 20cm? Area – B X H = 20 cm X 10 cm =200 cm2
What about Irregular Shapes? How do you find the area of this shape? First – Break shape into smaller REGULAR shapes. In this case a rectangle and two triangles. Now find the area of these smaller shapes. Add all three areas together to get your answer.
What about Irregular Shapes? How do you find the area of this shape? First – Break shape into smaller REGULAR shapes. In this case five rectangles. Now find the area of these smaller shapes. Add all five areas together to get your answer.