in a triangle /one side is x/one side is x+1/another side is 20/if it is true and what is value of x

Answer 1

If what is true?

Answer 2

I think this is the answer
x+x+1+20=180
2x+21=180
2x=180-21
2x=159
x=180/2
x=79.5 or if u round 80