IS 210,211,81,87 Relatiely prime?

Answer 1

210=2*3*5*7 composite
211 prime
81=3^4 composite
87 =3*29 composite

Answer 2

Do you mean Relatively Prime? If so, your question is phrased strangely. Are you asking if 210 and 211 are relatively prime, and if and 81 and 82 are also? As we know, relative primes have no common factors. Since 210 = 2*3*5*7 and 211 = 1*211, they are relatively prime. 81 = 3*3*3*3 and 87 = 3*29 and therefore are also relatively prime. If you're asking if all 4 are relatively prime, then the answer is no since more then one contain a factor of 3.

Answer 3

You have to give another integer for two numbers to be relatively prime.

What is the other integer?

Oh, I get it, You don't understand the conjugations of the verb "to -be."

Your question should be:

Are 210, 211, 81 and 87 relatively prime?

No, 210 and 81 are both divisable by 3.

Answer 4

I'm not totally happy with any of these answers, including the sarcastic one.

Yes I am, I just had another look at Falzoon's answer, and think it should get the 10 points, so ignore the rest of my answer.

I think the answer is "yes", because there isn't a factor common to all four numbers, but three of them are divisible by 3. Some of the answerers seem to believe that "relatively prime" can apply only to a pair of numbers, and they may be right, but it seems to me you could apply it to four numbers in the sense that I've used. In any case, even if you looked at the six possible pairs of numbers, the three pairs which include 211 are relatively prime, since it is a prime number.

Answer 5

Take the prime factorisation of each integer.

210 = 1 * 2 * 3 * 5 * 7
211 = 1 * 211
81 = 1 * 3 * 3 * 3 * 3
87 = 1 * 3 * 29

Integers that are relatively prime to each other,
have no common factor other than 1.

So, 211 is relatively prime to 210
and 211 is relatively prime to 81
and 211 is relatively prime to 87.

Those are referred to as being 'pairwise relatively prime',
because it refers to two integers.

But 210, 81 and 87 are NOT relatively prime to each other,
because they each contain the factor 3.
So there are no pairwise relative primes between 210, 81 and 87.

But there is no number that divides all of 210, 211, 81
and 87, so they ARE relatively prime, as a group.

This is referred to as being 'mutually relatively prime',
because it refers to more than two integers.

Answer 6

If you cannot find any common factor other than 1 for the four numbers, then the four numbers are relatively prime.

But 210, 81 and 87 are relatively prime because 3 is a common factor.

Answer 7

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