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Area of a rectangle Area of composite shapes Area of a right-angled triangle www.mathsrevision.com Simple Areas
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www.mathsrevision.com www.mathsrevision.com Starter Questions Starter Questions www.mathsrevision.com 34 o
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www.mathsrevision.com www.mathsrevision.com Area of a Rectangle www.mathsrevision.com Learning Intention Success Criteria 1.To be able to state area formula for a rectangle. 1. To come up with a formula for the area of a rectangle. 2.Use the formula to solve problems. 2.Apply formula correctly. (showing working) (showing working) 3.Answer containing appropriate units appropriate units
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Problem… General Jack’s Carpets Only £5 a square metre! How much for this one? ? www.mathsrevision.com
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3 rows of 6 squares Problem… 6 square metres = 3 x 6= 18 square metres = 1 square metre 3 m 6 m 1m How much for 18 square metres? 18 x £5 = £90 www.mathsrevision.com
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Area of a rectangle 6 = 18 m² 3 m 6 m 3 6 Area =lengthx breadth length breadth x 3 www.mathsrevision.com
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Example 1 11 cm 6 cm Area = length x breadth A = l x b A = 11 x 6 A = 66 cm² www.mathsrevision.com Find the area of the rectangle
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Example 2 12 cm Area = length x breadth A = l x b A = 12 x 12 A = 144 cm² www.mathsrevision.com Find the area of the square
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www.mathsrevision.com www.mathsrevision.com Starter Questions Starter Questions www.mathsrevision.com 123 o
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www.mathsrevision.com www.mathsrevision.com Learning Intention Success Criteria 1.Know area of a right-angled triangle formula Use the area of a rectangle formula to help us to come up with a formula to calculate the area of any right-angled triangle. 1. Use the area of a rectangle formula to help us to come up with a formula to calculate the area of any right-angled triangle. 2.Use formula to work out area of triangle. 3.Show all working and units. Area of A Right-Angled Triangle
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Area of a right-angled triangle Area of rectangle = l x b= 28 cm² 4 cm 7 cm = 7 x 4 Area of triangle = 14 cm² = ½ x 28 = ½ x Area of rectangle www.mathsrevision.com
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Area of triangle Short cut 4 cm 7 cm Area of triangle = 14 cm²= ½ x 28 = ½ x 7 x 4 Area Δ =x basex height ½ base height www.mathsrevision.com
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Example 1 10 cm 15 cm Area Δ=½ x base x height AΔ =½ x b x h AΔ = ½ x 15 x 10 AΔ = 75 cm² www.mathsrevision.com Find the area of the triangle
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Example 2 12 cm 8 cm Area Δ=½ x base x height AΔ =½ x b x h AΔ = ½ x 8 x 12 AΔ = 48 cm² www.mathsrevision.com Find the area of the triangle
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Now try worksheet Exercise 1 www.mathsrevision.com Area of a right-angled triangle
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www.mathsrevision.com www.mathsrevision.com Starter Questions Starter Questions www.mathsrevision.com 34 o
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www.mathsrevision.com www.mathsrevision.com Area of a Composite www.mathsrevision.com Learning Intention Success Criteria 1.To be able to use knowledge gained so far to find the area of more complicated shapes.. 1. To use knowledge to find area of more complicate shapes. 2.Show appropriate working. Made up of Simple shapes
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? Composite shapes 6 cm 10 cm 13 cm ? 3 cm www.mathsrevision.com
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6 cm ? 10 cm (1) (2) Area (1) = l x b= 60 cm²= 10 x 6 Area (2) = 9 cm² = ½ x 3 x 6 = ½ x b x h Area of shape = (1) + (2)= 69 cm²= 60 + 9 3 cm www.mathsrevision.com Composite shapes
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Example 1 Area (1)= =15 x 8 Area (2) = l x b l x b = 120 cm² =9 x 3 = 27 cm² Area of shape = (1) + (2) = 120 + 27 = 147 cm² 15cm 11cm 6cm 3cm (1) (2) ? 9cm 8cm ? Find the area of the shape
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Example 2 Area (1)= =20 x 12 Area (2) = l x b 12cm 20cm10cm 6cm (1) (2) l x b = 240 cm² =10 x 6 = 60 cm² Area of shape = (1) – (2) = 240 -60 = 180 cm² Find the area of the shape
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Now try worksheet Exercise 2 www.mathsrevision.com Composite shapes
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