Big Ideas Math Integrated I, 2016
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Big Ideas Math Integrated I, 2016 View details
2. Inductive and Deductive Reasoning
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Exercise 41 Page 458

Both arguments starts out with a true conditional statement. How do the arguments differ in the next two sentences?

Argument 2, see solution.

Practice makes perfect

Both arguments starts out with a true conditional statement. If two angles measure $30^(∘)$ and $60^(∘)$, then the angles are complementary. In the next two sentences, the arguments differ.

Argument 1

If we rewrite the second and third sentence into a conditional statement, we see that it is actually (although more specific) the converse of the first conditional statement. If $∠ 1$ and $∠ 2$ are complementary, then $m∠ 1=30^(∘)$ and $m∠ 2=60^(∘)$. This is not a true conditional statement, as complementary angles do not have to be 30^(∘) and 60^(∘). They could be any other measures as long as they have a sum of 90^(∘).

Argument 2

If we rewrite the second and third sentence into a conditional statement, we see that it is the same conditional statement as the first one. If $∠ 1=30^(∘)$ and $∠ 2=60^(∘)$ then $∠ 1$ and $∠ 2$ are complementary. Since the original conditional statement is true, this one must be as well. Therefore, Argument 2 is the correct answer.