Correct!

Please review the explanation below:

Answer: 4

You must recognize similar triangles in the diagram and set up the correct proportion, which could be expressed as: .

Letting AB be represented by x and substituting the other measures from the diagram, the proportion is then solved for the unknown measure: .

Cross-multiplying: 10x = 1000

Dividing by 10: x = 100

The final answer is 100 feet.