The length of the trail is 98.5 KM, all you need to do is divide the total distance by the number of times she went on it.
Answer:

Try to solve the similtanious equation to find the first term and the common difference, then use that information to figure out the 80th term... Update me if you need further help ...
Answer:
I need Help on this one too.
Step-by-step explanation:
Pythagorean Theorem is for right triangles
right triangles have a 90 degree angle in them
D is a right triangle