If this is supposed to be

Then this can simply be reduced to

by the double angle formula for cosine
The scale factor from the small one to the big one is 3
It's scientific notation, so 1.4x10^7 would be 14000000 <span />
Answer:
a. 4.33.
Step-by-step explanation:
If there is only one correct answer out of four alternatives, the expected proportion of correct answers is p =0.25
Sample size (n) = 100 questions
The standard deviation of a proportion 'p' is given by:

Applying the given data:

If X is the number of correct responses in 100 guesses, the standard deviation of X is:

The standard deviation of X is 4.33 questions.
Answer:

Step-by-step explanation:
The rectangle has been split into two right triangles. The hypotenuse of the triangle (the diagonal) is 18. The angle in the triangle is 30. All right triangles have unique relationships between their sides depending on the angles. This triangle must be a 30 - 60 - 90 triangle and its sides will be a scaled version of
.
The side 2 correspond to the hypotenuse of length 18. 2*9 = 18 and so the scale factor is 9. To find the remaining sides, multiply each side length by 9 from
.
It becomes
. So the rectangle is 9 by
.
The perimeter of the rectangle is 