Okay, So here we are given the LCM of 432 and with the help of that we need to find the LCM of both 432 and 84...
[tex] \sf \: 432 = 2 \times 2 \times 2 \times 2 \times 3 \times 3 \times 3[/tex]
[tex] \sf \: 84 = 2 \times 2 \times 3 \times 7[/tex]
[tex] \tt \: 432 \: and \: 84 = 2 \times 2 \times 2 \times 2 \times 3 \times 3 \times 7 \\ \tt = 1008[/tex]
Answer:
(i) 2² · 3 · 7
(ii) 3024
(iii) k = 16
(iv) 12 cm
Step-by-step explanation:
The first few prime numbers are: 2, 3, 5, 7, 11, 13, 17, ...
To find which prime numbers multiply together to make 84, start by dividing 84 by the first prime number, 2:
⇒ 84 ÷ 2 = 42
As 42 is not a prime number, we need to divide again:
⇒ 42 ÷ 2 = 21
As 21 is not a prime number, we need to divide again.
21 is not divisible by 2, so let's try dividing by the next prime number, 3:
⇒ 21 ÷ 3 = 7
As 7 is a prime number, we can stop.
Therefore, 84 is the product of:
⇒ 84 = 2 · 2 · 3 · 7
As 2 appears two times, we can write this using exponents:
⇒ 84 = 2² · 3 · 7
Lowest Common Multiple (LCM): The lowest multiple shared by two or more numbers.
Prime Factors Method of finding LCM
Step 1
Find the prime factorization of each number.
From part (i): 84 = 2² · 3 · 7
Given in part (ii): 432 = 2⁴ · 3³
Step 2
Write each number as a product of primes, matching primes vertically where possible:
[tex]\begin{array}{ r c c c c c c c ccccccccc}84&=& 2 & \cdot & 2 & \cdot & & & & & 3& \cdot & & & && 7\\\\432 &=& 2 & \cdot & 2 &\cdot & 2& \cdot & 2& \cdot & 3& \cdot & 3& \cdot & 3\\\\\cline{1-17} \\\sf LCM & = & 2 & \cdot & 2 &\cdot & 2& \cdot & 2& \cdot & 3& \cdot & 3& \cdot & 3 &\cdot & 7\end{array}[/tex]
Step 3
Bring down the primes in each column then multiply the factors to get the LCM:
⇒ LCM = 2 · 2 · 2 · 2 · 3 · 3 · 3 · 7
⇒ LCM = 2⁴ · 3³ · 7
⇒ LCM = 3024
From part (ii) we know that the prime factorization of 432 is:
432 = 2⁴ · 3³
A perfect cube is a number multiplied by itself three times.
One of the factors of 432 is a perfect cube → 3³.
Therefore,
[tex]\begin{aligned}432 & = 2^4 \cdot 3^3\\\\\implies \dfrac{432}{2^4} & = 3^3\\\\\dfrac{432}{16} & = 3^3\end{aligned}[/tex]
So we need to divide 432 by 2⁴ to get the perfect cube 3³.
Therefore,
⇒ k = 2⁴
⇒ k = 2 · 2 · 2 · 2
⇒ k = 16
To find the largest possible length of the side of the square, we need to find the greatest common factor of 432 and 84.
Prime Factors Method of finding GCF
Step 1
Find the prime factorization of each number.
From part (i): 84 = 2² · 3 · 7
Given in part (ii): 432 = 2⁴ · 3³
Step 2
Write each number as a product of primes, matching primes vertically where possible:
[tex]\begin{array}{ r c c c c c c c ccccccccc}84&=& 2 & \cdot & 2 & \cdot & & & & & 3& \cdot & & & && 7\\\\432 &=& 2 & \cdot & 2 &\cdot & 2& \cdot & 2& \cdot & 3& \cdot & 3& \cdot & 3\\\\\cline{1-17} \\\sf GCF & = & 2 & \cdot & 2 & \cdot & & & & & 3& & & & && \end{array}[/tex]
Step 3
Bring down the primes in the columns where both numbers have the factor, then multiply the factors to get the GCF:
⇒ GCF = 2 · 2 · 3
⇒ GCF = 12
Therefore, the largest possible length of the side of the square is 12 cm.