geometry

Straight line = 180

180 = 4x+30     +  8x+90         solve for 'x'  then   MON = 8x+90 ^o

So we know that angle LON is a straight angle. This means that angle LON is 180 degrees. 

 

We are given that angle LOM is equal to 4x+30 degrees. So, we know that the sum of LOM+MON= 180 degrees:

 

4x+30+8x+90=180

 

12x+120=180

 

12x=60

 

x=5

 

Now, we can substitute this in the equation for MON!

 

8x+90= 8(5)+90=40+90=130 degrees