Answer:
r=4
Explanation:
Firstly, you see that the line is 180 degrees and there's a 90 degree angle and 55 degree angle. So to find the value of r, you need to find how much degrees are in that section, so 180-90 is 90 and 90-55 is 35, so that section is 35 degrees. So, the equation is (9r-1)=35, so I add 1 to both sides, 9r=36 then I divide both sides by 9, and 36 divided by 9 is 4. So r=4.