Question

Which of the following can be a common denominator for the fractions LaTeX: \frac{3}{5} and LaTeX: \frac{4}{9}?

Answer 1

45.

Explanation:

Find the LCM (Least Common Multiple):

• We can use a factorization tree or make a list of values.

Lets list out the multiples of 5 and 9 (Denominators)

5: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50.

9: 9, 18, 27, 36, 45, 54, 63, 72, 81, 90

45 is the least common multiple.

Multiply the denominator to get to 45, same applies for numerator:

`(3 * 9)/(5 * 9) = (27)/(45)`

`(4 * 5)/(9 * 5) = (20)/(45)`

45 is the least common multiple that you can use for your denominators.