Challenge! Given a segment of length 1 unit, construct a segment of length square root 2 units

Assume segment AB has a length of 1 unit. Construct another segment that has a length of square root 2 units.
Hint: There is a theorem you will need to obtain the value of square root 2. Read the poem to see what that theorem is.
[br]I live over 2,000 years ago,[br]mathematics was part of my soul,[br]many discoveries I came to know,[br]geometry theorems were my goal.[br][br]But one I am credited with the most,[br]it is a polygon with 3 sides,[br]include 90 degrees and you are getting close,[br]in the equation the answer abides.[br][br]For Pythagoras is my name,[br]and this theorem brought me fame,[br]now square the two legs and then you’ll see,[br]how the hypotenuse came to be.[br][br]

Information: Challenge! Given a segment of length 1 unit, construct a segment of length square root 2 units