We have the triangle 30° - 60° - 90°.
The lenght of the sides are in proportion: 

I can't read that language but I'll guess it says write a second degree equation then solve for n when d=10.



Answer: n² - 3n - 20 = 0
That doesn't factor so there is no integer n solution.
That means there are no polygons with 10 diagonals.

Answer:
its -160
Step-by-step explanation:
:)
Letter B or π is an irrational number, therefore it's the answer.