Calculating Actual Lengths from Scale Drawings

Mr. Buffington introduces the concept of scale factor, explaining it as a constant used to multiply measurements to obtain new measurements in scale drawings. He discusses its applications in blueprints, maps, and other fields. The video includes a sample problem involving a house's front wall and a practice problem with a rock throw, both demonstrating how to calculate actual sizes using scale factors. The lesson concludes with a recap of the key concepts.

What is a scale factor?

• A variable used to add measurements

• A constant used to multiply measurements

• A constant used to divide measurements

• A variable used to subtract measurements

If a rectangle is 4 meters by 1 meter and the scale factor is 2, what is the new length of the longer side?

• 8 meters

• 6 meters

• 4 meters

• 2 meters

Which of the following is NOT an application of scale drawings?

• Blueprints

• Maps

• Outer space models

• Cooking recipes

In the given example, if 1 inch equals 4 feet, what is the actual size of a front wall that measures 13 inches in the drawing?

• 65 feet

• 52 feet

• 39 feet

• 26 feet

What is the scale factor if 1 inch equals 4 feet?

• 1:2

• 1:3

• 1:4

• 1:5

If the measured distance is 7 and 3/4 inches and the scale factor is 1 inch equals 5 feet, what is the actual distance?

• 35 and 3/4 feet

• 36 and 3/4 feet

• 37 and 3/4 feet

• 38 and 3/4 feet

What is the first step in solving a scale drawing problem?

• Subtract the measurements

• Multiply the measured size by the scale factor

• Divide the measurements

• Add the measurements

What happens to the complexity of scale drawing problems when distances and scale factors are fractions?

• They become unsolvable

• They become more complicated

• They remain the same

• They become easier

What is the key rule to remember when multiplying fractions or decimals in scale drawing problems?

• Always add the fractions first

• Always subtract the decimals first

• Follow the rules for multiplying fractions or decimals

• Ignore the fractions or decimals

What is the final step to find the actual size in a scale drawing problem?

• Add the scale factor to the measured size

• Multiply the measured size by the scale factor

• Subtract the scale factor from the measured size

• Divide the measured size by the scale factor