C. 100 because a quadrilateral must add up to 360. :)
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:
the answer is 4-x^2
Step-by-step explanation:
-2x
and 2x cancel out
Answer: C (0,3) because the two lines meet at the point (0,3)
Answer:
x=5
Step-by-step explanation:
We simplify the equation to the form, which is simple to understand
3x+5-5=20-5
We move all terms containing x to the left and all other terms to the right.
+3x=+20-5-5+5
We simplify left and right side of the equation.
+3x=+15
We divide both sides of the equation by 3 to get x.
x=5