Respuesta :

theking7x
The reference angle is : π/9


Explain

Now the given angle is

-8 π/ 9

Now we can see that the angle is negative ( given angle) and it is in the third quadrant then find the reference angle we need to add π to it

Reference angle : - 8 π/ 9

9 π -8 π/ 9

Subtract


π/9