Answer:
To find the volume of a cube one must multiply all three dimensions together. Here we know two of the dimensions and the volume but not the third dimension. First I multipl together to two known dimensions: 3/4 x 1/2 = 3/8. Next I divide the volume by this answer by using the reciprocal of 3/8 and multipling. 21/32 x 8/3 = 7/4 by cancelling the 32 with the 8 and the 21 with the 3. Now 7/4 must be changed into a mixed number. Divide the numerator by the denominator and write the remainder as a fraction. 7/4 = 1 3/4.