A decagon has 10 sides (think decade and decathlon). From the center of the decagon we draw the radii and in doing so we take the area of the decagon and divide it into 10 congruent Triangles.
The angles around the center add up to 360 because they form a circle and since there are 10, they each measure 36 degrees. So the answer to the first part (the angle between the radii) is 36 degrees.
Each of these triangles has two equal sides (both radii) so is Isosceles. That means that the base angles are congruent. So the two angles that are left in each triangle must measure the same. Since the angles in a triangle add up to 180 degrees, we know that the two remaining angles are together equal to 180-36=144 degrees. Since they are equal in measure they each measure 72 degrees.
Thus the answer to the second part, trhe measure of the angle between a radius and the side of the polygon is 72 degrees.
Answer: a. 90°
Step-by-step explanation:
We know that the in a circle, the measure of an inscribed angle is half the measure of the central angle with the same intercepted arc.
In the problem∠XYZ is the inscribed angle
∠XYZ=
⇒ ∠XYZ=
Since XZ is a diameter of the circle which is a line segment, thus ∠XZ=180°
∴ ∠XYZ=
∴ ∠XYZ=
Therefore, a. 90° is the measure of ∠XYZ.
Yes the answer is C. -2 to the left with open circle and 4 to the right with closed circle
The general term of an arithmetic sequence is,

Where ,
= nth term.
= First term
and d = common difference.
The given sequence is: 57, 66, 75, 84, 93, ...
Here
= 57,
d = 66 - 57 = 9
We need to find the 250th term. So, n = 250.
Next step is to plug in these values in the above formula. Therefore,

= 57 + 249 * 9
= 57 + 2241
= 2298
Therefore, 250th of this sequence is 2298
Hope this helps you!