Area & Perimeter
Perimeter The distance around a shape – The sum of the lengths of all the sides in a shape – Measured in units of length i.e. Feet, miles, meters, etc
Area The space within a shape – Measured in units of length squared i.e. ft 2, mi 2, m 2, etc
Why feet squared? Units for area are always squared because they are describing how many little squares it would take to fill in the shape. – For example: 75 ft 2 means that there are 75 squares that are 1 foot on each side needed to cover the space. 1 foot
Area of a square, rectangle & parallelogram A = bh – Base and Height ALWAYS must form a 90 degree angle! 6 meters 15 meters 12 meters Area = bh = 6 x 12 = 72 m 2
AREA OF A PARALLELOGRAM Welcome. Today you’re going to discover the formula for area of a parallelogram. h b Click to Continue
AREA OF A PARALLELOGRAM To do this let’s cut the left triangle and… h b Click to Continue
slide it… AREA OF A PARALLELOGRAM h h b Click to Continue
slide it… AREA OF A PARALLELOGRAM h h b
slide it… AREA OF A PARALLELOGRAM h h b
slide it… AREA OF A PARALLELOGRAM h h b
…thus, changing it to a rectangle. What is the area of the rectangle? AREA OF PARALLELOGRAM h b
Area of a triangle – Base and Height ALWAYS must form a 90 degree angle! (be perpendicular) 8 feet Area = bh ÷ 2 = 8 x 9 ÷2 = 36 ft 2 9 feet 12 feet
What is the area of the square? A = bh = 2 x 2 = 4 in 2
What is the perimeter of the square? P = s + s + s + s = = 8 inches
What is the area of the rectangle? A = bh = 8 x 3 = 24 cm 2
What is the perimeter of the rectangle? P = b + b + h + h = = 22 centimeters
What is the area of the shape? A = bh = 12 x 5 = 60 cm 2
What is the area of the shape? A = bh = 7 x 10 = 70 in 2
What is the area of the shape? Area = bh ÷ 2 = 4 x 15 ÷ 2 = 30 in 2
What is the area of the shape? Area = bh ÷ 2 = 6 x 9 ÷2 = 27 cm 2
What is the area of the shape? Area = bh ÷ 2 = 8 x 5 ÷2 = 20 in 2
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