Final answer:
The suitable scale for Juan to draw a bridge approximately 20 cm long is 1:20. This scale implies that each unit in the drawing represents 20 units of the actual structure. The scale factor helps determine the proportional relationship between the size of the drawing and the real-life size of the object being drawn.
Step-by-step explanation:
When determining which scale Juan should use to draw a bridge that is approximately 20 centimeters long, it's important to understand the scale factor of the drawing. Given that the scale factor for the drawing is 1/200, the proportion between the scale and the actual size should be considered. For example, if the actual length of a structure is 200 meters, then using the scale factor of 1/200, the drawing would be 1 meter. To fit into a 20 centimeters drawing, however, Juan should use the scale that allows for a 20 centimeters representation of the actual size.
To answer the student's schoolwork question on scale drawings, we need to select a scale where the ratio of the drawing to the actual structure is such that when the actual length is multiplied by this ratio, the result equals to approximately 20 centimeters. The correct scale factor in this scenario would be option b) 1:20. This means that for every 20 units on the real bridge, there will be 1 unit on the drawing.
Additionally, here are some scale factor related problems:
- For a model with an actual length of 24 feet and a scale factor of 1/36, the model should be ½ foot or 6 inches long.
- If the scale factor was 1/72, the model should be ¼ foot or 3 inches long.
- A 2.5-meter pipe in a drawing with a scale factor of 1/100 would be 2.5 centimeters long.
- A housefly 8 millimeters in actual size drawn with a scale factor of 10 would be 80 millimeters long in the drawing, which is also 8 centimeters.