I would characterize the relationship as a positive correlation. I would probably give it a 0.7, which means that the correlation is relatively strong. Also, this is an example of correlation, not causation, because there is not scientific proof that doing homework more will cause better grades. Hope this helps!
The product of positive and negative numbers is negative.
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The sign of a product will be negative if an odd number of factors of the product are negative. 1 negative factor is an odd number of negative factors, so the result is negative.
We know that it is A because the two smaller angles are being added, and we know the sum is 90 degrees. The only equation that satisfies both of these is A.
