Answer:
7.87X10^3
Step-by-step explanation:
^ means to the power of
A. figure ABCD is similar to figure A'B'C'D'
I believe that the answer is -18.
Answer:
B. The rate of change of item II is greater than the rate of change of them I
Double angle (or half angle, depending how you look at it) identities:



So we have



Note that when taking the square root, we should take into account that that could yield two possible solutions, but we know
and
, so it's also the case that
.
Also, the reason we have equality in the last step can be explained like so:

(not unlike the process used to complete the square)