This cylinder is cut by the plane shown. The plane is parallel to the base of the cylinder. What is the shape of the cross-section?
A) circle.
B) parallelogram.
C) rectangle.
D) square.

take the logarithm of both sides (the base of the log doesn't matter):

apply the exponent property - this says that :

distribute the log terms on both sides:

group like terms together:

divide through both sides by the coefficient on :

you can do some additional rewriting here using the properties of the logarithm to simplify things if you like:

i think the answer is 90 hope this