Uh is there a picture cuz we can't know what's a vetex angle if we don't see a pic
-11 = a + 7 Given
-7 -7 Subtract 7 on each side to cancel out +7 and isolate variable
-18 = a Answer
Prove.
-11 = -18 + 7 Plug in variable value
-11 = -11
True.
A reasonable number between 18 and 23 is 20. 69 minutes is 3 times 23 minutes, so we multiply the 20 by 3, getting an estimate of 60 cars.
