3.13 To determine surface measurements by means of measuring and

Natural sciences

Matter, measuring and reactions

Educator section

Memorandum

1. My method:

Area = l × b

= 6 cm × 10 cm

= 60 cm ²

2. A = ℓ × b

Area = length multiplied by width

One also uses this formula to determine the area of a rectangle.

3. 25 cm ²

Leaner section

Content

Activity: to determine surface measurements by means of measuring and calculation [lo 1.2]

You have probably heard people referring to the size of a house as equal to 150 square meters (150 m²). Do you know what is meant when people speak of square metres?

Examine the sketch:Each square of the grid represents one square metre. A square metre is a four-sided plane geometric figure having four equal sides of 1 metre in length.When we say that the surface of fig. X is 100 m², we mean that we can fit one hundred single m² into it. One could count the number of squares in the grid, or block, to find out what the size of the surface is, but there is a quicker method for finding the answer.If the length of each side of the larger surface is 10 m, you could calculate the number of blocks (square metres) that can fit into the larger surface area (100) by multiplying the length of the one side (10 m) by the length of the other side (10 m x 10 m = 100 square metres).

Fig. X

1. How would you determine the surface area of the following rectangle?

(Each block is 1 cm²)

The length of this rectangle is 100 mm and the breadth is 60 mm.

My method:

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(5)

2. What is the meaning of the following formula: A = ℓ b?

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3. Apply the following formula to determine the surface area of the given triangle:

b represents the length of the base

h represents the height of the perpendicular line

• My answer (estimated):______________________________________________
• My answer (calculated according to the given formula):____________________

(2)

Assessment

Learning Outcome 1: The learner will be able to act confidently on curiosity about natural phenomena, and to investigate relationships and solve problems in scientific, technological and environmental contexts.

Assessment Standard 1.2: We know this when the learner conducts investigations and collects data: organises and uses apparatus/equipment or sources to gain and record information.