2007-11-04 16:36:36 · 13 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
Thanks everyone! :)
2007-11-04 16:46:30 · update #1
The lowest common denominator is the smallest number that both 12 and 21 will both divide into and have a whole number quotent.
The way to find the LCD is to factor each number into its prime factors. 12 is 2x2x3 and 21 is 3x7.
Then look for the largest power of each prime factor and use them as your factors for the LCD.
So the LCD is 2x2x3x7 or 84.
If you were looking for the largest common factor, you would also factor the numbers and see what power of a prime factor is the largest. In this example 3 is the only common factor and is therefore also the largest common factor.
Hope this helps.
2007-11-04 16:58:31 · answer #1 · answered by TheProfessor 2 · 2⤊ 0⤋
Thanks for a very simple question. Follow my step below: The lowest common denominator is the smallest number that all three numbers will divide into with a whole number quotient. The process used is to first break each number into its prime factors. 12 = 2 x 2 x 3, 15 = 3 x 5, and 21 = 3 x 7 The Lowest common denominator will be 2 x 2 x 3 x 5 x 7 = 420 420/12 = 35, 420/15 = 28, and 420/21 = 20 35, 28, and 20 are whole numbers. 12, 15, and 21 also have a common factor, 3. Since it is the largest prime number that divides into all three numbers, it is called the largest common factor. Sometimes the largest common denominator is confused with the largest common factor. I hope you got the best answer for your question. Have a nice day!
2016-05-27 10:12:48 · answer #2 · answered by ? 3 · 0⤊ 0⤋
1
2007-11-04 16:41:45 · answer #3 · answered by KD 1 · 0⤊ 2⤋
3
2007-11-04 16:39:43 · answer #4 · answered by bob oso 2 · 1⤊ 3⤋
3
2007-11-04 16:38:27 · answer #5 · answered by guru 5 · 1⤊ 3⤋
Ok the LCD is....
12, 24, 36, 48, 60, 72, 84, 96, 108
21, 42, 63, 84
The LCD is 84
2007-11-04 16:40:42 · answer #6 · answered by Anonymous · 2⤊ 0⤋
84
2007-11-04 16:39:05 · answer #7 · answered by twigg1313 3 · 3⤊ 0⤋
3. it goes into 12 4 times and 21 7 times
2007-11-04 16:38:54 · answer #8 · answered by Miss Understood 7 · 0⤊ 3⤋
they are both divisible by 3 but the LCD is 84.
12 x 7 = 84
21x 4 = 84
2007-11-04 16:42:55 · answer #9 · answered by Chicosgurrl 1 · 2⤊ 0⤋
least common multiple is 84
least common multiple and lowest common denominator are the same thing
everyone that is saying 3 is saying the greatest common divisor. not the least common denominator
2007-11-04 16:41:00 · answer #10 · answered by radne0 5 · 1⤊ 0⤋