Raphael bought a 2/3 pound bag of sugar, and he used 3/4 of it for baking.
To find out how much sugar he used, we need to multiply the fraction of the bag that he used (3/4) by the weight of the bag (2/3 pounds):
(3/4) x (2/3) pounds
To simplify this fraction multiplication, we can cancel out the factor of 3 in the numerator and the denominator:
(1/4) x (2/1) pounds
= 2/4 pounds
= 1/2 pound
Therefore, Raphael used 1/2 pound of sugar for baking.