You can tell what type of rock is in an area and its age range by reviewing the area's color and and comparing it to information given in the legend.
a. letters
b. lines
c. shape
d. size

the answer would be the third option, "no, ariel should have added 9^2 and 12^2 and compared that to 15^2."

this is found through the pythagorean theorem, which is a^2 + b^2 = c^2.

this is the correct way of solving the problem:

9^2 + 12^2 = 15^2

81 + 144 = 225

225 = 225