Answer:

Step-by-step explanation:
We can form a right triangle and use basic trig for a right triangle to solve this problem:
, where
is the height of the tree.
Solving, we get:
.
18 - (-f) = 91
Subtracting a negative value changes to addition:
18 + f = 91
Subtract 18 from both sides:
F = 73
Answer: I think it is -0.4
Step-by-step explanation:
If she can drive 4180 miles in <em>two </em>weeks, it would make sense that she would drive an average of <em>half </em>that distance in <em>one </em>week. Half of 4180 is 2090, so she averaged 2090 miles each week.
The common factor would be 3 because 3 is the highest multiple of 15 and 9