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Area and Perimeter of Compound Shapes. Compound Shapes. Can you describe what a compound shape is?. Shapes Compound shapes. Recap: How do you work out the area of. Area of rectangle = Length x Width Perimeter of rectangle = 2(Length + Width)
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Compound Shapes Can you describe what a compound shape is? • Shapes • Compound shapes
Recap: How do you work out the area of... Area of rectangle = Length x Width Perimeter of rectangle = 2(Length + Width) or L + W + L + W
Area of triangle = (Base x Perpendicular Height) ÷ 2 Perimeter of triangle = Add all the side lengths
Area of Circle = π r2 where r is the radius Perimeter of Circle = Circumference of the circle = 2 π r or π d where d is the diameter of the circle
a h b Area of trapezoid = h(a+b) 2 Perimeter of trapezoid = Add all the side lengths
Compound Shapes • A compound shape is one that is made up of other shapes. • To find the area of a compound shape, you need to split it up into shapes you know: • Label each section. • Write down all dimensions. • Find the areas. • A: • B: • A + B = __________ 7cm 6cm 13cm Remember, there is often more than one way to split up a shape! 4cm
Compound Shapes 4cm • Label each section. • Write down all dimensions. • Find the areas. • A: • B: • A + B = __________ 4cm 7cm 6cm
Compound Shapes • Label each section. • Write down all dimensions. • Find the areas. • A: • B: • A + B = __________ 8cm 13cm 15cm
Compound Shapes • Label each section. • Write down all dimensions. • Find the areas. • A: • B: • C: • A + B + C = __________ 4cm 22cm 15cm 18cm 25cm
Compound Shapes 15cm • Label each section. • Write down all dimensions. • Find the areas. • A: • B: • C: • A + B + C = __________ 14cm 8cm 20cm 9cm 18cm
Alice is putting a wallpaper border around her bedroom. She must find the __________ of her bedroom in order to purchase the correct amount of border. perimeter 12 ft 3 ft ? 4 ft 6.5 ft ? 3.5 ft 8 ft P = 8 ft + 6.5 ft + 12 ft + 3 ft + 4 ft + 3.5 ft Alice needs to purchase 37 feet of border.
Detective LeRue must investigate a crime committed at the local park. How many square meters of ground must he cover when looking for clues? Total area = 28 m2 + 16 m2 + 21 m2 = 65 square meters Is there another way of finding this area? Area = 4 m (7 m) Area = 4 m(4 m) 4 m 3 m 3 m Area =3 m(7 m) 4 m 28 m2 7 m 21 m2 7 m 16 m2
Step 1: Find area of big rectangle • Step 2: Find area of smaller rectangle • Step 3: Subtract the smaller area from the larger area Total area = 77 m2 – 12 m2 = 65 square meters How can we use subtraction to find the area? 11 m 4 m 4 m 3 m 3 m Area = 3 m(4 m) 4 m 7 m 7 m Area =7 m (11 m) =12 m2 = 77 m2
Detective LaRue must isolate the crime scene, how much tape will he need? Perimeter = 7m + 4 m + 3 m+ 4 m + 3 m + 3 m + 7 m + 11 m Detective LaRue needs 42 meters of crime scene tape. 4 m 3 m ? 3 m 4 m 7 m 7 m ?
1. Find the area and perimeter 6 cm 2 cm 5 cm Area = 74 cm2 Perimeter = 40 cm 9 cm 5 cm
30 in 30 in 20 in 70 in 2. Find the area and perimeter Area = 2300 in2 Perimeter = 240 in
3. Find the area and perimeter 3 yd 2 yd 3 yd 4.5 yd Area = 30 yd2 Perimeter = 29 yd 8 yd
4. Find the area and perimeter. Use 3.14 for π Area = 88.26 ft2 Perimeter = 38.84 ft
5. Find the area and perimeter Area = 212.75 km2 Perimeter = 69.7 km 14 km 4 km 18 km
6. Find the area and perimeter Area = 97.5 m2 Perimeter= 36 m 3 m 12.5 m 7.5 m 13 m
7. Find the area of the arrow. Area = 90 ft2
8. Find the Area of the Shaded Region. Use 3.14 for π . Area = 437.5 mm2