Question

#6 is the equation i need help with

Answer 1

360°

Explanation:

external angles of a triangle are always equal to 360°

you can also prove this

180-∡9=∡6

180-∡11=∡8

+180-∡10=∡7

540 -(∡9+∡10+∡11)=∡6+∡7+∡8

we know that the sum of the interior angles (∡6, ∡7, ∡8) is equal to 180°

540-(∡9+∡10+∡11)=180

540-180=(∡9+∡10+∡11)

360=∡9+∡10+∡11