Three lines met at a point . if the sum of two of the lines of the angles formed is 163°, what is the size of the third angle

The lengths of nails produced in a factory are normally distributed with a mean of 4.91 centimeters and a standard deviation of 0.05 centimeters. find the two lengths that separate the top 4% and the bottom 4%. these lengths could serve as limits used to identify which nails should be rejected. round your answer to the nearest hundredth, if necessary.

How to do this , and can some one explain

If a || b and e || f , what if the value of y ?