# Find the perimeter. Areas Grade 7 - CIC 15-Feb-14 Area of a Rectangle 31 2 43 3 3 6 12 X = X = X = BAh B B h h B h B = base h = height Must learn formula.

## Presentation on theme: "Find the perimeter. Areas Grade 7 - CIC 15-Feb-14 Area of a Rectangle 31 2 43 3 3 6 12 X = X = X = BAh B B h h B h B = base h = height Must learn formula."— Presentation transcript:

Find the perimeter.

15-Feb-14 Area of a Rectangle 31 2 43 3 3 6 12 X = X = X = BAh B B h h B h B = base h = height Must learn formula ! 1 cm Area = base x height A = B x h

Find the area of each rectangular shape below. 100 m 50 m 120 m 40 m 1 2 3 4 5 8½ cm 5½ cm 90 feet 50 feet 210 cm 90 cm Not to scale. 5 000 m 2 4500 ft 2 4 800 m 2 46.75 cm 2 18 900 cm 2

base height base height Area of a Parallelogram The area of a parallelogram = the area of a rectangle on the same base. Area = base x height

8 cm 14 mm 1.5 m 12 cm5 mm 2.1 m Find the area of each parallelogram below. 1 2 3 Area = 8 x 12 = 96 cm 2 Area = 14 x 5 = 70 mm 2 Area = 1.5 x 2.1 = 3.15 m2m2

base height Area of a triangle = ½ base x height Area of a Triangle The area of a triangle = ½ the area of the surrounding rectangle/parallelogram

Area of a Triangle rectangle area = 2 + 2 triangle area = ½ rectangle area base height Area of a triangle = ½ base x height The area of a triangle = ½ the area of the surrounding rectangle/parallelogram

Area = ½ x 8 x 9 = 36 cm 2 Area = ½ x 10 x 12 = 60 cm 2 Area = ½ x 14 x 16 = 112 cm 2 Area = ½ x 3.2 x 4.5 = 7.2 m 2 Find the area of the following triangles. 8 cm 10 cm 14 cm 12 cm 9 cm 16 cm Area = ½ b x h 3.2 m 4.5 m 7 mm 5 mm Area = ½ x 7 x 5 = 17.5 mm 2

The Area of a Trapezium Area = ½ the sum of the parallel sides x the perpendicular height A = ½(a + b)h a b h b ½h a Area of trapezium = area of parallelogram A = ½(a + b)h

The Area of a Trapezium Area = ½ the sum of the parallel sides x the perpendicular height A = ½(a + b)h a b h ½ah ½bh Area = ½ah + ½bh = ½h(a + b) = ½(a + b)h Area = ½ (8 + 12) x 9 = ½ x 20 x 9 = 90 cm 2 Area = ½(7 + 5) x 6 = ½ x 12 x 6 = 36 cm 2 Find the area of each trapezium 1 8 cm 12 cm 9 cm 2 5 cm 7 cm 6 cm 3 5 cm 3.9 cm 7.1 cm Area = ½(3.9 + 7.1) x 5 = ½ x 11 x 5 = 27.5 cm 2

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