Check the picture below.
so, the center of the circle is the midpoint of that diametrical segment, and half that length is the radius.

![\bf ~~~~~~~~~~~~\textit{distance between 2 points} \\\\ \begin{array}{ccccccccc} &&x_1&&y_1&&x_2&&y_2\\ % (a,b) &&(~ -2 &,& -4~) % (c,d) &&(~ 3 &,& 8~) \end{array}~~~ % distance value d = \sqrt{( x_2- x_1)^2 + ( y_2- y_1)^2} \\\\\\ d=\sqrt{[3-(-2)]^2+[8-(-4)]^2}\implies d=\sqrt{(3+2)^2+(8+4)^2} \\\\\\ d=\sqrt{25+144}\implies d=\sqrt{169}\implies d=13\qquad\qquad \qquad \stackrel{radius}{\frac{13}{2}}](https://tex.z-dn.net/?f=%5Cbf%20~~~~~~~~~~~~%5Ctextit%7Bdistance%20between%202%20points%7D%0A%5C%5C%5C%5C%0A%5Cbegin%7Barray%7D%7Bccccccccc%7D%0A%26%26x_1%26%26y_1%26%26x_2%26%26y_2%5C%5C%0A%25%20%20%28a%2Cb%29%0A%26%26%28~%20-2%20%26%2C%26%20-4~%29%20%0A%25%20%20%28c%2Cd%29%0A%26%26%28~%203%20%26%2C%26%208~%29%0A%5Cend%7Barray%7D~~~%20%0A%25%20%20distance%20value%0Ad%20%3D%20%5Csqrt%7B%28%20x_2-%20x_1%29%5E2%20%2B%20%28%20y_2-%20y_1%29%5E2%7D%0A%5C%5C%5C%5C%5C%5C%0Ad%3D%5Csqrt%7B%5B3-%28-2%29%5D%5E2%2B%5B8-%28-4%29%5D%5E2%7D%5Cimplies%20d%3D%5Csqrt%7B%283%2B2%29%5E2%2B%288%2B4%29%5E2%7D%0A%5C%5C%5C%5C%5C%5C%0Ad%3D%5Csqrt%7B25%2B144%7D%5Cimplies%20d%3D%5Csqrt%7B169%7D%5Cimplies%20d%3D13%5Cqquad%5Cqquad%20%5Cqquad%20%20%5Cstackrel%7Bradius%7D%7B%5Cfrac%7B13%7D%7B2%7D%7D)
Answer:
<em>The second choice is correct. It can be factored as:</em>

Step-by-step explanation:
<u>The Difference of Squares Method for Factoring</u>
The expression:

Is a widely used method to factor binomials that are expressed as the subtraction of two perfect squares.
The condition for a binomial to be factored by using this method is that both terms must have an exact square root and they must be subtracted.
The last two choices are not valid because they are not a subtraction but an addition.
The first choice is not valid because none of the terms is a perfect square.
The second choice is correct. It can be factored as:

Answer:
9. 70° 10. 90° 11. 110°
Step-by-step explanation:
12. 25°
13. 95°
14. 20°
Answer: A. f(n) = 4 ∙ 2n-1
Step-by-step explanation:
because the 1st term is 4 according to your image, and then you will have to multiply that by its common difference and using your table, to get from 4 to 8 then 8 to 16 you would multiply by 2, and you would finally multiply that by n or known as the number of terms and 1 making the equation. f(n) = 4 ∙ 2n-1 I hope this is very helpful for everyone.
Im not positive but I think the answer is a.