A 30 60 90 triangle has its shorter side equal to one half the hypotenuse.
So, if hypotenuse = 11 cm then shorter side = 5.5.
Source:
http://www.1728.org/trig2.htm
Dimensional Analysis is the way you want to go

Answer:
Divide total length by length of each piece to get the number of pieces.
= 30 ÷ 2/3
multiply by reciprocal of 2/3
= 30 * 3/2
= 90/2
= 45
ANSWER: Total number of pieces that can be cut is 45.