... shared by 28 and 21 .Practice QuestionWhat are the common factors of 48 and 36?a. 1, 2, and 3b. 1, 2, 3, and 6c. 1, 2, 3, 6, and 12 d. 1, 2, 3, 6, 8, and 12 e. 1, 2, 3, 4, 6, 8, and 12 Answerc. ... because 8 ϫ 3 ϭ 24 and 12 ϫ 2 ϭ 24 .ᎏ18ᎏϭ 1 ϫᎏ38ᎏϫ 3 ϭᎏ 2 34ᎏConvert fraction.ᎏ11 2 ᎏϭ 1 ϫᎏ1 2 2ᎏϫ 2 ϭᎏ 2 24ᎏConvert fraction.ᎏ 2 34ᎏϩᎏ 2 24ᎏϭᎏ 2 54ᎏAdd numerators ... 28 .The factors of 21 are 1, 3, 7, and 21 .The common factors of 28 and 21 are therefore 1 and 7 because they are factors of both 28 and 21 .The greatest common factor of 28 and 21 is therefore...