How does a change in the scale influence the size of the drawings?.You will need the Same Plot, Different Drawings blackline master for this activity.įocus the discussion on patterns or features students noticed in the different scale drawings.
The relationships between scale, lengths in scale drawings, and area in scale drawings are all important examples of the mathematical structure (MP7) of scale drawings.
By dividing the actual area represented by the scale drawing by the area of their scale drawing. By visualizing what a \(1 \times 1\) centimeter square represents at a given scale (e.g., at a scale of 1 cm to 5 m, each 1 cm 2 represents \(5 \boldcdot 5\), or 25 m 2). Students are likely to determine this value in two ways: They think about how many square meters of actual area are represented by one square centimeter on each drawing. The group then orders the different drawings and analyzes them. This activity serves several purposes: to allow students to practice creating scale drawings at given scales, to draw attention to the size of the scale drawing as one of the values in the scale changes, and to explore more fully the relationship between scaled area and actual area.Įach group member uses a different scale to calculate scaled lengths of the same plot of land, draw a scale drawing, and calculate its scaled area. Since it is difficult to measure the length of these feet very precisely, these measurements should not be reported with a high level of precision the nearest centimeter would be appropriate. Next, invite students to share their estimates for the length of the large foot. The way a measurement is reported reflects how the measurement was taken. The problem with reporting the measurement in this way is that someone who sees this might misinterpret it and imagine that an extremely accurate measuring device was used to measure the foot, rather than this ruler. With the ruler, it is possible to guess that the hundredths place is an 8. Make sure students understand that reporting measurements to the nearest \(\frac\) of an inch or to the hundred-thousandths of a centimeter would not be appropriate (i.e., show that the ruler does not allow for these levels of precision).Ĭhoice E of 23.48 cm may merit specific attention. 
If students consider B, C, or E to be an appropriate measurement, ask them to share how to get such a level of precision on the ruler. After each response, poll the class on whether they agree or disagree. Consider displaying the picture of the ruler for all to see and recording students' responses on it. Select a few students to share the measurements they think would be appropriate based on the given ruler.
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