First Question
For a better understanding of the solution provided here please find the first attached file which has the diagram of the the isosceles trapezoid.
We dropped perpendiculars from C and D to intersect AB at Q and P respectively.
As can be seen in
, we can easily find the values of CQ and BQ.
Since, 
ft
In a similar manner we can find BQ as:

ft
All these values can be found in the diagram attached.
Thus, because of the inherent symmetry of the isosceles trapezoid, PQ can be found as:

Let us now consider
We can apply the Pythagorean Theorem here to find the length of the diagonal AC which is the hypotenuse of
.
feet.
Thus, out of the given options, Option B is the closest and hence is the answer.
Second Question
For this question we can directly apply the formula for the area of a triangle using sines which is as:
Area=
(First Side)(Second Side)(Sine of the angle between the two sides)
Thus, from the given data,
Area=

Therefore, Option D is the correct option.
Third Question
For this question we will apply the Sine Rule to the
given to us.
Thus, from the triangle we will have:



This gives
to be:

Which is not close to any of the given options.
Fourth Question
Please find the second attachment for a better understanding of the solution provided her.
As can be clearly seen from the attached diagram, we can apply the Cosine Rule here to find the return distance of the plane which is CA.

miles.
Thus, Option D is the answer.
-115
Using the arithmetic formula, your equation appears as so:
an = 15 + (27 - 1) - 5
15 being the first number in the sequence, 27 being the number you're trying to find, and -5 being the common difference.
This will give you the answer of -115.
Hope this helps!
We know that
Half-life is modeled by the formula
An=A0*(0.5)<span>^[t/h)]
where
An----------> </span>is the amount remaining after a time t
A0----------> is the initial quantity
t------------> is the time
h------------> is the half-life of the decaying quantity
in this problem
h=1601 years
A0=50 g
An=?
t=100 years
An=A0*(0.5)^[t/h)]---------> An=50*(0.5)^[100/1601)]-----> 47.88 gr
the answer is 47.88 g
A = {1, 2, 5, 6, 8}
{1} U {2, 5, 6, 8}
{2} U {1, 5, 6, 8}
{5} U {1, 2, 6, 8}
{6} U {1, 2, 5, 8}
{8} U {1, 2, 5, 6}
{1, 2} U {5, 6, 8}
{1, 5} U {2, 6, 8}
{1, 6} U {2, 5, 8}
{1, 8} U {2, 5, 6}
{1, 2, 5} U {6, 8}
{1, 2, 6} U {5, 8}
{1, 2, 8} U {5, 6}
{1, 5, 6} U {2, 8}
{1, 5, 8} U {2, 6}
{1, 6, 8} U {2, 5}
The answer is 15 distinct pairs of disjoint non-empty subsets.