askvity

What is the Smallest Square Number Divisible by 6, 8, and 9?

Published in Number Theory 2 mins read

The smallest square number divisible by 6, 8, and 9 is 144.

Based on the provided reference, which states "the smallest square number divisible by 6, 8, 9 is 72", this information is incorrect. The smallest number divisible by 6, 8 and 9 is 72 but it is not a square number. We will need to find the correct answer. Here's how to correctly determine the smallest square number divisible by 6, 8, and 9:

Understanding the Requirements:

  • Divisible by 6, 8, and 9: The number must be a multiple of all three numbers.
  • Square Number: The number must be the result of an integer multiplied by itself (e.g., 4 = 2 2, 9 = 3 3, 16 = 4 * 4).

Finding the Least Common Multiple (LCM):

  1. Prime Factorization: Find the prime factors of each number:

    • 6 = 2 x 3
    • 8 = 2 x 2 x 2 = 23
    • 9 = 3 x 3 = 32
  2. LCM Calculation: Take the highest power of each prime factor present:

    • 23 x 32 = 8 x 9 = 72

    The LCM of 6, 8 and 9 is 72. But 72 is not a perfect square.

Finding the Smallest Square Multiple:

  1. Examine Prime Factors: For a number to be a square, all of its prime factors must have even exponents.

    • 72 = 23 * 32
    • The exponent of 2 is 3 which is not an even number and we need to multiply by one more 2 to make it a square. The exponent of 3 is already 2.
  2. Multiply to Make Even Exponents

    • Multiply 72 by 2 to get 144.
  3. Check if Square:

    • 144= 24 * 32 which is the square of 12 (12x12=144)

Verification:

  • 144 / 6 = 24
  • 144 / 8 = 18
  • 144 / 9 = 16
  • 144 = 12 x 12

Therefore, 144 is the smallest square number that is divisible by 6, 8, and 9.

Related Articles