Help please!! i really don't get this question. (attached below) I will report any irrelevant answers, but I will give brainliest!

9

Step-by-step explanation:

Rotational symmetry is when a shape has the same orientation after being rotated.

For example, an equilateral triangle rotated 120° will line back up with itself.  A square rotated 90° will also return to its original orientation.  Same with a pentagon rotated 72°.

Basically, an n-gon rotated by a multiple of 360°/n will return to its original position.

θ = k 360°/n

For the first rotation:

160° = k 360°/n

160 / 360 = k / n

4/9 = k/n

For the second rotation:

120° = k 360°/n

120 / 360 = k / n

1/3 = k/n

For the third rotation:

80° = k 360°/n

80 / 360 = k / n

2/9 = k/n

For the fourth rotation:

280° = k 360°/n

280 / 360 = k / n

7/9 = k/n

The total rotation angle is -160°.

160 = k 360/n

160 / 360 = k / n

4/9 = k/n

Comparing the denominators, n must be the smallest multiple of 3 and 9.  Therefore, n = 9.

dc=6 square root of 3 and ac is 12 square root 3

c and d

step-by-step explanation:

square root of 3/2 = 18/c

cross multiply to get 18*2=√3*c

36/√3 * √3/√3 = c

c= 36*√3/3

c=12√3

4+4+2x

or

2x+8

step-by-step explanation: