Answer:
-3/4
Step-by-step explanation:
Answer:
180 degrees
Step-by-step explanation:
All the angles should add up to 360°.
8x+10x+9+21x-12+90=360°
Group like terms together.
So,8x+10x+21x+9+90-12=360
39x+87=360
39x=360-87
39x=273
x=7
You can not work it out because we do not know the shape or the other properties of this poster.
Sorry for not being able to answer it.