
Cross multiplying, we get:

Thus the value of y for given proportion is 18.
It’s been awhile since I’ve done a problem like this but I believe it’s solved as below:
The area of a circle is equal to πr2. That will tell you the entire area of the circle. Then you would need to divide that by 2 to get the area of the 180° arc.
So, the area of this circle is 153.94 square meters. If you divide that by 2 (since 180° is half of a circle) you would get 76.97 square meters.
Y=2 is the answer. Fhjfnsbsnsjcjcnds
We want to get b alone so I would start by multiplying 2 to get it on the other side of the = sign. So then I have 2L=a-b. I would subtract a on both sides and then I would have 2L-a= -b. We don't want a -b so I would multiply everything by -1 so then the answer would then be a positive b= -2L+a