Area for a circle is

. We will fill in each area and then solve for the radius.

and

. ∴

and r = 13. For b,

and

.

, ∴ r = 17. For c,

, and

. ∴,

and r = 11. For d,

, and

. ∴,

so r = 25. And there you have it!
Answer: D (bottom option)
Not Congruent
Step-by-step explanation:
Assuming the trapezoids are to scale, they are not the same shape. This means that they could not be congruent even if they were centered on top of each other.
Add up 3+3=6, number has to be bigger than 9 so the answer is false.
Answer:
There are two possibilities:
and 
and 
Step-by-step explanation:
Mathematically speaking, the statement is equivalent to this 2-variable non-linear system:


First,
is cleared in the first equation:

Now, the variable is substituted in the second one:

And some algebra is done in order to simplify the expression:


Roots are found by means of the General Equation for Second-Order Polynomials:
and 
There are two different values for
:






There are two possibilities:
and 
and 
<span>8 + 5n = -72
5n = -72 - 8
5n = - 80
n = -80/5
n = -16</span>