The answer is 90 + 45 because BOC is a right angled triangle where angle BOC is 90 and angle BOK is 45 because 90 ÷2. A OK Is a right angled triangle so angle AOB is 90 as well so to find angle AOK we plus 90 and 45 which is 135 degrees.
I believe they call it a recurring number, for example, infinity is a recurring number.
It's scientific notation, so 1.4x10^7 would be 14000000 <span />