To measure and calculate a perimeter

Mathematics

Measurement and time

Length

Educator section

Memorandum

1. 88

2. 8,8

3. 0,88

4. 11

5. 110

6. 1,1

7. 0,11

8. 0,111

9. 1 000 m

10. 10 mm

11. 1 000 m

12. 1 000 000 mm

13. 208

14. 8

15. 39

Leaner section

Content

In this module we are going to measure with the aid of various instruments.

We are going to measure:

• length,
• mass,
• circumference,
• area,
• volume,
• content,
• temperature and
• time.

Activity: to measure and calculate a perimeter [lo 4.4.3, lo 4.8.1]

1. An ant must walk from A to B, then to C, D, E and again to A (right around – perimeter).

1.1 What instrument will you use to calculate how far the ant walks?

1.2 Now calculate the distance the ant has walked.

_____________________________________________________________________

_____________________________________________________________________

1.3 In what unit did you measure? _____________________________________

1.4 What unit did your friend use? _____________________________________

2. Take a look at the following figures. Are you able to tell the educator what the "ordinary" name for each one (excepting the square) is?

square

2.1 These shapes are regular. Why?

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

2.2 Calculate the perimeter of each shape (remember the units). Write the name of each shape, followed by the answer.

(a) __________________________________________________________________

(b) _________________________________________________________________

(c) __________________________________________________________________

(d) _________________________________________________________________

2.3 If the perimeter of a square can be calculated by means of the formula 4 x side, which formula would be used for each of these shapes? Write the name of the shape, followed by the answer.

(a) __________________________________________________________________

(b) _________________________________________________________________

(c) __________________________________________________________________

(d) _________________________________________________________________

2.4 What do we call the following shape?

_____________________________________________________________________

2.5 Can you perhaps deduce a formula for calculating the perimeter of a rectangle?

_____________________________________________________________________

REMEMBER THIS!

A square also happens to be a rectangle. It just happens to be one with four equal sides. All squares are rectangles, but all rectangles are not square.

3. Here are a few irregular shapes.

3.1 Why do we say that these shapes are irregular?

_____________________________________________________________________

3.2 Now calculate the perimeter of each of the irregular shapes.

A: __________________________________________________________________

B: __________________________________________________________________

C: __________________________________________________________________

Assessment

Learning Outcome 4: The learner will be able to use appropriate measuring units, instruments and formulae in a variety of contexts.

Assessment Standard 4.4: We know this when the learner estimates, measures, records, compares and orders two-dimensional shapes and three-dimensional objects using S.I. units with appropriate precision for:

4.4.3: length using millimetres (mm), centimetres (cm), metres (m) and kilometres (km);

Assessment Standard 4.8: We know this when the learner investigates and approximates (alone and/or as a member of a group or team):

4.8.1: perimeter using rulers or measuring tapes.