Exploring Computing Areas from Scale Drawings

Lesson 19 focuses on computing actual areas from scale drawings by identifying the scale factor. The lesson includes examples of enlargement and reduction, demonstrating how the scale factor affects the area. It concludes with a practical application involving a basketball court and provides a homework assignment.

What is the key idea in this lesson regarding the relationship between scale factor and area?

• The ratio of areas is half the scale factor.

• The scale factor is the cube of the ratio of areas.

• The ratio of areas is the square of the scale factor.

• The scale factor is the same as the ratio of areas.

In Example 1, what is the scale factor when the actual picture is 4 units by 3 units and the scale drawing is 8 units by 6 units?

• 1

• 4

• 2

• 3

What is the area of the actual picture in Example 1?

• 12 units squared

• 48 units squared

• 36 units squared

• 24 units squared

In Example 2, what is the scale factor when the actual picture is 6 units by 9 units and the scale drawing is 2 units by 3 units?

• 1/5

• 1/2

• 1/3

• 1/4

What is the area of the scale drawing in Example 2?

• 24 units squared

• 18 units squared

• 12 units squared

• 6 units squared

In Example 3, what is the scale factor when the actual triangle has a base of 9 units and height of 6 units, and the scale drawing has a base of 12 units and height of 8 units?

• 3/2

• 2/3

• 3/4

• 4/3

What is the area of the actual triangle in Example 3?

• 36 units squared

• 45 units squared

• 27 units squared

• 18 units squared

What conclusion can be drawn about the relationship between scale factor and area?

• The ratio of areas is the scale factor multiplied by itself.

• The scale factor is the ratio of areas divided by itself.

• The scale factor is the ratio of areas multiplied by itself.

• The ratio of areas is the scale factor divided by itself.

In the basketball court example, what is the area of the planned half court using method one?

• 750 feet squared

• 600 feet squared

• 500 feet squared

• 700 feet squared

Which method involves squaring the scale factor to find the area of the planned half court?

• Method 3

• Method 2

• Method 1

• All of the above