In order to solve this, we need the sum of all interior angles which can be found by using the following formula where "n" is the number of sides the polygon has...
Now we use the formula and get...
180(n - 2) = 180(4 - 2) = 180(2) = 360
Now in order to find angle "x," we just substract the values of the other angles from 360, and so we get...
The total pages she wants to finish (360) minus the pages she has read (112.5) equals to 247.5 Then divide it by the 45 (the rate of pages she reads per hour) 5.5 hours.