A scale model of the Golden Gate Bridge in San Francisco Bay has a main span that is 20 inches long. If

the main span of the bridge is 4200 feet long, what is the scale of the model?

4200 / 20 = 210

1 inch = 210 feet

To find the scale of the model, we need to compare the length of the model's main span to the length of the actual bridge's main span. We can set up a proportion to solve for the scale.

Let's assume the scale of the model is denoted by 'x'. Since the main span of the model is 20 inches and the main span of the actual bridge is 4200 feet, we can set up the following proportion:

x/20 = 4200/1

To solve for 'x', we can cross-multiply and then divide to isolate 'x':

x = (4200 * 20) / 1
x = 84000 / 1
x = 84000

Therefore, the scale of the model is 1:84000. This means that 1 unit on the model represents 84000 units on the actual Golden Gate Bridge.

1 inch = 210 ft

1 ft = 2520 ft

4200/20=210

210*12=2500
1 inch = 2500 ft

4260 ft