Answer:
5 km
Step-by-step explanation:
It helps to draw a diagram.
The triangle between Stamford, Newport, and Amanda's house is a right triangle with one leg of length 12 and hypotenuse 13. The Pythagorean theorem can be used to find the remaining leg:
13² = 12² + (distance to Newport)²
169 -144 = (distance to Newport)²
√25 = 5 = distance to Newport
Newport is 5 km from Amanda's house.
_____
It can be useful to remember this right triangle. 5-12-13 right triangles show up in a number of algebra and geometry problems.
