What is the LCM of 66, 78, and 90?

Answer 1

66=2*3*11
78=2*3*13
90=2*3^2*5
LCM (66, 78, 90) = 2*3^2*5*11*13 = 12,870

Answer 2

We need a definition.

The LCD stands for lowest common multiple.

What exactly is the LCM? The least common multiple (LCM) of two numbers is the smallest number (not zero) that is a multiple of both.

Line up your numbers vertically.

66 =

78 =

90 =

We are looking for the SMALLEST multiple that appears for all three numbers given. To do this, multiply each given number in an increasing order.

Like this:

66 x 1, 66 x 2, 66 x 3, etc
78 x 1, 78 x 2, 78 x 3, etc
90 x 1, 90 x 2, 90 x 3, etc

Keep doing this using a calculator until you come across a number that all three share.

Got it? The LOWEST number they share will be your LCM.

Guido

Answer 3

2 ¦ 66, 78, 90
3 ¦ 33, 39, 45
3 ¦ 11, 13, 15
5 ¦ 11, 13, 5
11¦11, 13, 1
13¦ 1, 13, 1
xx¦ 1, 1, 1

Then multiply all the numbers on the left of the vertical bar, you get:

2*3*3*5*11*13 = 12870

Answer 4

66=2*3*11
78=2*3*13
90=2*3*15

so L.C.M. =2*3*11*13*15=12870

Answer 5

an A+