me solve 3.11 please. Discrete Heres the ref-PROPOSITION 2. Given two numbers not prime to one another, to find their greatest common measure. Let AB, CD be the two given numbers not prime to one another. Thus it is required to find the greatest common measure of AB, CD. If now CD measures AB - and it also measures itself - CD is a common measure of CD, AB. And it is manifest that it is also the greatest; for no greater number than CD will measure CD. But, if CD does not measure AB, then, the less of the numbers AB, CD being continually subtracted from the greater, some number will be left which will measure the one before it. For a unit will not be left; otherwise AB, CD will be prime to one another [VIl, II, which is contrary to the hypothesis.