2006-11-30 14:40:43 · 7 answers · asked by coolio 1 in Science & Mathematics ➔ Mathematics
get the prime factors of each...
12= 2x2x3
21=7x3
39=13x3
get the common prime factor of each... their common factor is 3.
so multiply 3 with the remaining factors...
3x2x2x7x13=1092
their LCM is 1092
2006-11-30 14:50:46 · answer #1 · answered by Steph_kinse 2 · 0⤊ 0⤋
The trick: get the prime factorization of each number, stack them up on top of each other, and put all "same" numbers aligned with each other. To explain:
12 = 2 x 2 x 3
21 = 3 x 7
39 = 3 x 13
Now, line up the values
12 = 2 x 2 x 3
21 = ||||||||||||||||3 x 7
39 = ||||||||||||||||3 x|||||||13
And now make a single long product from the aligning
2 x 2 x 3 x 7 x 13 = 1092
2006-11-30 14:45:58 · answer #2 · answered by Puggy 7 · 1⤊ 0⤋
What Is 12 21
2017-02-20 22:23:49 · answer #3 · answered by ? 4 · 0⤊ 0⤋
12 = 2*2*3
21 = 3*7
39 = 3* 13
_________________
2*2*3*7*13 = 1092 LCM
2006-11-30 14:52:59 · answer #4 · answered by euclidjr 2 · 0⤊ 0⤋
I think 1 is the least multiple of 12,21 and 39............................
2006-11-30 14:42:52 · answer #5 · answered by Intelligentia 2 · 0⤊ 1⤋
The lowest number that can be divided into all three numbers, in this case 3.
2006-11-30 14:54:43 · answer #6 · answered by rudy m 1 · 0⤊ 1⤋
3.
3X4=12
3X7=21
3X13=39
2006-11-30 14:43:37 · answer #7 · answered by kyla m 1 · 0⤊ 1⤋