Elena's office is 25 miles southeast of her home. Which of the following correctly uses a Pythagorean triple to find out how many miles Elena needs to drive south and then east to get from home to work? (1 point)

• 7 miles south and 18 miles east
• 5 miles south and 24.5 miles east
• 7 miles south and 24 miles east
• 5 miles south and 20 miles east

1 answer

To determine which option accurately uses a Pythagorean triple to represent Elena's 25-mile diagonal distance from home to her office, we need to check whether the given combinations of south and east distances satisfy the Pythagorean theorem, \( a^2 + b^2 = c^2 \), where \( c \) is the distance from home to office.

Given that her office is 25 miles away, we have \( c = 25 \).

Let's evaluate each option:

  1. 7 miles south and 18 miles east: \[ a^2 + b^2 = 7^2 + 18^2 = 49 + 324 = 373 \] Since \( \sqrt{373} \) is not 25, this option is incorrect.

  2. 5 miles south and 24.5 miles east: \[ a^2 + b^2 = 5^2 + 24.5^2 = 25 + 600.25 = 625.25 \] Since \( \sqrt{625.25} \) is not 25, this option is incorrect.

  3. 7 miles south and 24 miles east: \[ a^2 + b^2 = 7^2 + 24^2 = 49 + 576 = 625 \] Since \( \sqrt{625} = 25 \), this option is correct.

  4. 5 miles south and 20 miles east: \[ a^2 + b^2 = 5^2 + 20^2 = 25 + 400 = 425 \] Since \( \sqrt{425} \) is not 25, this option is incorrect.

From the options given, the correct choice that uses a Pythagorean triple is: 7 miles south and 24 miles east.