![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step1.JPG\")
Method 1:
\List the factors of each number.
\Factors of 21: 3, 7, 21
\Factors of 160: 2, 4, 5, 8, 10, 20, 40, 80, 160
\Identify the greatest common factor.
\There are no common prime factors.Two numbers aiways have 1 as a common factor.So, the GCF is 1, and the numbers are relativety prime. ![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step2.JPG\")
Method 2:
\Write the prime factorization of each number.
\21 = 1 × 3 × 7.
\160 = 1 × 2 × 2 × 2 × 2 × 2 × 5.
\There are no common prime factors.Two numbers aiways have 1 as a common factor.So, the GCF is 1, and the numbers are relativety prime.![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/solution.JPG\")
There are no common prime factors.Two numbers aiways have 1 as a common factor.So, the GCF is 1, and the numbers are relativety prime.