Because it is 1/8 of a turn of 360 degrees
The take off formula of a 45 degree elbow pipe, will depend on what the pipe is on. Sometimes a 45 degree pipe will need a 90 degree right angle turn to come off.
it has 45 90 135 180 225 270 315 and 360 degree turn semetry
One half of a right angle is a 45 degree angle.
45 ft lbs65 ft lbs65 ft lbs90 degree turn45 ft lbs65 ft lbs65 ft lbs90 degree turn
45 degree angle
A 45 degree elbow will not make a right angle, but two will, if connected in line so that they continue the turn in the same direction. (45o + 45o = 90o, a right angle.)
A right angle is 90 degrees, so 45 degrees is half a right angle turn.