Maths Term 5 Week 2: Perimeter and AreaLet’s do this!💪🏽

We hope you had a lovely weekend!

Recap… What is area and perimeter?

Perimeter is the distance around a 2D shape. It’s working out how far an ant would have to walk if it walked around the entire outside of the shape.

Area is the working how much space is in the centre of a shape. It’s working out how big the garden space is inside a fenced off area!

Watch this as a reminder!

Examples...Perimeter

If you wanted to work out the perimeter of this shape (let’s imagine it’s in meters), your

calculation would be:

7 + 3 + 7 + 3 = 20 meters.

Area

If you wanted to work out the area, the calculation would be slightly different. You would multiply the height (how tall the shape is) by the width (how wide/fat it is). You may have done this by counting squares in previous years but multiplying the height by the width is a much quicker way of doing this! In cm, your calculation would be:

5 x 3 = 15cm2 <- NOTE THE 2 when working in area. You must use this too!

3 chilli extra information...

Area formula

w x hw = widthh = height

As you know, the perimeter is the distance around the outside of the shape and area is the space inside it. People have created formulas to represent this. The letters just represent numbers - you can substitute in any number!

Activity 1 - MondayLO: I can measure and calculate the perimeter of composite rectilinear shapes (rectangles that are put together to make another shape) in cm and metres

Use the previous slides to help you complete this activity. Remember, perimeter is finding out how long the outside of the shape is (how far an ant would have to walk).

1 chilli

Task 1 - each square is 1 cm. What is the total perimeter?

Task 2 - draw four composite rectilinear shapes with a perimeter of 20cm. No ruler - no worries. Write what each side could be!

Activity 1 - MondayLO: I can measure and calculate the perimeter of composite rectilinear shapes (rectangles that are put together to make another shape) in cm and metres

Use the previous slides to help you complete this activity. Remember, perimeter is finding out how long the outside of the shape is (how far an ant would have to walk).

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Task 2: Draw 4 rectilinear shapes (like the ones you’ve just worked on) that have the perimeter of 26 cm. Label the sides No ruler - no worries. Write what each side could be!

Task 1: Using the lengths we have given you, work out the perimeter of the shape. All lengths are cm.

Activity 1 - MondayLO: I can measure and calculate the perimeter of composite rectilinear shapes (rectangles that are put together to make another shape) in cm and metres

Use the previous slides to help you complete this activity. Remember, perimeter is finding out how long the outside of the shape is (how far an ant would have to walk).

3 chilli

Task 2: Draw 4 rectilinear shapes (like the ones you’ve just worked on) that have the perimeter of 30cm. They must have at least 12 sides! No ruler - no worries. Write what each side could be!

Task 1: Each square is worth 1 meter. Work out the perimeter for each of the 10 shapes. Convert 5 of your perimeters into cm.

Here is some squared paper which you can use for task 2 if you want to and do not have squared paper. (They are also on printable sheets on the website) Each square can be worth 1cm. If you don’t have a printer, do not worry - you can just draw them in your books and label the sides.

Monday challenge…

Activity 2 - TuesdayLO: I can calculate the area of a rectangle

Don’t forget that area is calculated by multiplying the height and the width of the shape (h x w = area).

Show your working.

1 chilli - complete all the shapes

2&3 chilli - complete a, b and c

Activity 2 - TuesdayLO: I can calculate the area of a rectangle

Don’t forget that area is calculated by multiplying the height and the width of the shape (h x w = area). If you’ve got the area and one of the sides, what calculation could you do to find the missing side? What is the opposite to multiplication?

2/3 chilli - complete all

Activity 2 - TuesdayLO: I can calculate the area of a shape

Don’t forget that area is calculated by multiplying the height and the width of the shape (h x w = area). Doing this, you would calculate the area of the WHOLE shape. Here, you only need to find half because the triangle is HALF of the rectangle… What could you do to the answer for the whole area to only find half? If you’re still stuck, take a look here: How do you work out the area of a triangle?

FYI 3 chilli - the formula is: ½ x (w x h)

⅔ chilli extension - complete all

Tuesday challenge…

Activity 3 Example - area of composite shapesFinding the Area of a Composite Figure - please watch. This explains how to find the area of composite

shape (a shape made up of simpler shapes).

Step 1 - break the shape up into simple shapes.

Step 2 - find the area of each shape- you may have to calculate missing sides (the video will explain how - don’t be put off by the letters, it’s just an easy way to refer to each line)

Step 3 - add the areas together!

Activity 3 - Wednesday LO : I can calculate the area of composite shapes

Lana wants to carpet her dolls house. Can you work out which room would need the most carpet? Show your workings!

1 chilli

Activity 3 - Wednesday LO : I can calculate the area of composite shapes

Lana wants to carpet her dolls house. Can you work out which room would need the most carpet?

Show your workings!

2&3 chilli

3 chilliTask 2: draw a composite a shape that has an area of

50 cm2. It doesn’t have to be to scale.

Wednesday challenge…

Activity 4 - Thursday LO: I can calculate the area of irregular shapesTo find the area of an irregular shape, you need to look at the number of squares that are completely inside the shape and those that are partly inside it.

In our example, each square is going to be worth 1cm.

Step 1 - find the number of whole squares (10).

10 x 1cm2 = 10cm2

Step 2 - find the number of part squares (22)

22 x ½ cm2 = 11cm2 (because they’re not full squares).

Step 3 - add the whole and half squares together

10cm2 + 11cm2 = 21cm2.

The estimated area of this irregular shape is 21cm2! If you’re still unsure, see the video on the next slide to help you!

Find the area of this irregular shape in cm.

Step 1 - find the number of whole squares.

There are 17 that I’ve crossed off in pink - this helps me to keep track of the ones I have counted and the ones I haven’t.

Step 2 - find the number of part squares

I counted 23 parts of squares. I mark them with dots so I don’t confuse them with the whole numbers. Because they are not full squares, I half this number because I cannot count them as wholes (as it’s only an estimate, this is ok). So I have the number 11.5.

Step 3 - add the whole and half squares together

17 + 11.5 = 28.5m2

The area of Hare island is 28.5m2

Activity 4 - Thursday LO: I can calculate the area of irregular shapes

Using the technique just shown to you, estimate the

area of these irregular shapes. Your answers can be within a

1cm2 range of the correct answer to be classed as

correct so take your time!

1, 2, 3 chilli

Can you construct a ‘Pirate Island’ to be used as part of a treasure map for a new game? Each square represents 4 m2.

The island must include the following features and be of the given approximate measure:

● Circular Island 180 m2● Oval Lake 58 m2● Forests with a total area of 63 m2 (can be split over more than one space)● Beaches with a total area of 92 m2 (can be split over more than one space)● Mountains with a total area of 57 m2● Rocky coastline with total area of 25 m2

Use the squared paper on the next slide if you do not have any.

Activity 4 - Thursday LO: I can calculate the area of irregular shapes

⅔ chilli optional extension

Thursday challenge...

Activity 5 - Friday LO: I can apply my knowledge of perimeter and area to word problems

Top tips: underline the key information in the question. Try drawing out what the question is telling you. Remember the difference between area and perimeter and the correct units for each one!

1. Two rectangles have a perimeter of 20 cm. In both, the sides measure whole

numbers of centimetres. Give possible measurements for the sides of the two rectangles.

2. My room is L-shaped. The longest side is 4 metres. The next longest is 3 metres.

Find the perimeter.

1 chilli - choose 3 problem solving questions to complete. Show your workings. 2 chilli - choose 4-5 problem solving questions to complete. Show your workings.

3 chilli - complete all 6 problem solving questions as well as the challenge. Show your workings.

3. Sam has two photos. One has an area of 49cm2. The other has an area of 56cm2. A side length of one photo is equal to one of the sides of the other. What are the side lengths of the two photos? 4. The area of a rectangle is 45 cm2. If one side is 4cm longer than the other, what is the perimeter of the rectangle? 5. Mary has an oval table. She wants to find its area as accurately as she can. Write 2 or 3 sentences explaining how she might do this. 6. A box exactly holds 75 centimetre cubed dice. Inside, it has a square base with sides 5cm. What is its inside height? 3 chilli challengeIf the wood is ½ cm thick and the box has a lid, how much space will the box take up in my bag?

Final Friday challenge…

Have a lovely weekend!