1956 AMC 12 Problem 33

Attempt Problem 33 of the 1956 AMC 12 below, then check your answer against the professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 1956 AMC 12 solutions, or check the answer key.

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33.

The number 2\sqrt2 is equal to:

a rational fraction

a finite decimal

1.414211.41421

an infinite repeating decimal

an infinite non-repeating decimal

Answer: E
Concepts:irrational numbersdecimal expansionssquare roots
Difficulty rating: 1340
Small Hint:

Recall what kind of decimal expansion every rational number has

Big Hint:

The number 2\sqrt2 is irrational, so its decimal neither terminates nor repeats

Solution:

The number 2\sqrt2 is irrational. A rational number has a decimal expansion that either terminates or eventually repeats, whereas an irrational number has an infinite non-repeating decimal expansion. The finite decimal 1.414211.41421 is only an approximation.

Thus, the correct answer is E.

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