The explicit rule for given sequence is:

Further explanation:
We have to determine first of all if the sequence is arithmetic or geometric.
- If the difference of two consecutive terms is same then the sequence is arithmetic sequence
- If the ratio of two consecutive terms is same then the sequence is geometric sequence
Given sequence is:
12,22,32,42

The common difference is 10 which is same for all consecutive terms. So the sequence is an arithmetic sequence.
The general formula for arithmetic sequence is:

Putting the values of a1 and d

The explicit rule for given sequence is:

Keywords: Arithmetic sequence, Common Difference
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<span>No, it doesn't. To find out if it's a right angled triangle, we use Pythagorean triple. It states that the square of the hypotenuse (the longest side) is equal to the sum of the squares of the opposite and adjacent sides. Obviously, the longest side, which is our hypotenuse is 24. So we want to find out whether the square of our hypotenuse is equal to the sum of the squares of the other two sides i. e 13 and 21.
24^ 2 = 576 ; 13^2 = 169 ; 21^2 = 441;
So is 576 = 169 + 441. An emphatic No: hence the triangle isn't right angled since it doesn't satisfy pythagorean triple.. A^2 is not equal to B^2 + C^2 where a is the hypotenuse and b and c the opposite and adjacent sides.</span>
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