Question
Find Greatest Common Divisor of 1045 and 1265, using prime factorization.
Answer
The GCD of given numbers is 55.
Explanation
Step 1 : Find prime factorization of each number.
$$\begin{aligned}1045 =& 5\cdot11\cdot19\\[8pt]1265 =& 5\cdot11\cdot23\\[8pt]\end{aligned}$$(view steps on how to factor 1045 and 1265. )
Step 2 : Put a box around factors that are common for all numbers:
$$\begin{aligned}1045 =& \color{blue}{\boxed{5}}\cdot\color{red}{\boxed{11}}\cdot19\\[8pt]1265 =& \color{blue}{\boxed{5}}\cdot\color{red}{\boxed{11}}\cdot23\\[8pt]\end{aligned}$$Step 3 : Multiply the boxed numbers together:
$$ GCD = 5\cdot11 = 55 $$This solution can be visualized using a Venn diagram.
The GCD equals the product of the numbers at the intersection.
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