9. Magma rises upward through the crust because a. the magma is less dense than surrounding rock.
b. magma is more dense than surrounding rock.
c. magma is the same density as the surrounding rock.
d. the surrounding rock is porous.

It's A (the magma is less dense than surrounding rock).

answer; european crusades;

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