Answer:
66 m
Explanation:
ok so if you think about it, when she runs diagonal she's creating a triangle where she is running along the hypotenuse. we can now use the Pythagorean Theorem a^2 + b^2 = c^2 to solve for the other side with two of them being known.
plug values in
100^2 + w^2 = 120^2
square known values
10,000 = w^2 = 14,400
subtract 10,000 from both sides
w^2 = 4400
take the square root
w = 66 (rounded to the nearest whole number)