Simple Areas Area of a rectangle Area of a right-angled triangle www.mathsrevision.com Area of composite shapes

Starter Questions www.mathsrevision.com 34o www.mathsrevision.com

Area of a Rectangle www.mathsrevision.com Learning Intention Success Criteria 1. To come up with a formula for the area of a rectangle. To be able to state area formula for a rectangle. Apply formula correctly. (showing working) www.mathsrevision.com Use the formula to solve problems. Answer containing appropriate units www.mathsrevision.com

General Jack’s Carpets Problem… General Jack’s Carpets www.mathsrevision.com How much for this one? ? Only £5 a square metre!

How much for 18 square metres? Problem… 1m 1m = 1 square metre 6 m 6 square metres 3 m 6 square metres 6 square metres www.mathsrevision.com 3 rows of 6 squares = 3 x 6 = 18 square metres 18 x £5 = £90 How much for 18 square metres?

6 3 Area of a rectangle 6 x 3 = 18 m² Area = length x breadth www.mathsrevision.com 6 x 3 = 18 m² Area = length x breadth

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

Example 2 12 cm Area = length x breadth A = l x b A = 12 x 12 A = 144 cm² www.mathsrevision.com 12 cm Find the area of the square

Starter Questions www.mathsrevision.com 123o www.mathsrevision.com

Area of A Right-Angled Triangle Learning Intention Success Criteria 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. Know area of a right-angled triangle formula 2. Use formula to work out area of triangle. www.mathsrevision.com 3. Show all working and units. www.mathsrevision.com

right-angled triangle Area of a right-angled triangle 4 cm 7 cm www.mathsrevision.com Area of rectangle = l x b = 7 x 4 = 28 cm² Area of triangle = ½ x Area of rectangle = ½ x 28 = 14 cm²

Area of triangle Short cut 4 cm height base 7 cm www.mathsrevision.com Area of triangle = ½ x 7 x 4 = ½ x 28 = 14 cm² Area Δ = ½ x base x height

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 10 cm AΔ = 75 cm² www.mathsrevision.com 15 cm Find the area of the triangle

Example 2 8 cm 12 cm Area Δ=½ x base x height AΔ =½ x b x h AΔ = ½ x 8 x 12 12 cm AΔ = 48 cm² www.mathsrevision.com Find the area of the triangle

right-angled triangle Area of a right-angled triangle Now try worksheet Exercise 1 www.mathsrevision.com

Starter Questions www.mathsrevision.com 34o www.mathsrevision.com

Area of a Composite www.mathsrevision.com Made up of Simple shapes Learning Intention Success Criteria 1. To use knowledge to find area of more complicate shapes. To be able to use knowledge gained so far to find the area of more complicated shapes.. www.mathsrevision.com Show appropriate working. www.mathsrevision.com

Composite shapes 10 cm 6 cm ? ? www.mathsrevision.com 3 cm 13 cm

Composite shapes www.mathsrevision.com Area (1) = l x b = 10 x 6 10 cm 6 cm (1) 6 cm ? (2) 3 cm www.mathsrevision.com Area (1) = l x b = 10 x 6 = 60 cm² Area (2) = ½ x b x h = ½ x 3 x 6 = 9 cm² Area of shape = (1) + (2) = 60 + 9 = 69 cm²

Example 1 Area (1)= l x b =15 x 8 = 120 cm² Area (2) = l x b =9 x 3 ? 8cm (1) Area (2) = l x b =9 x 3 = 27 cm² (2) Area of shape = (1) + (2) = 120 + 27 ? 9cm = 147 cm² Find the area of the shape

Example 2 Area (1)= l x b =20 x 12 = 240 cm² Area (2) = l x b =10 x 6 Area of shape = (1) – (2) = 240 -60 (1) = 180 cm² Find the area of the shape

Now try worksheet Exercise 2 Composite shapes Now try worksheet Exercise 2 www.mathsrevision.com