Question

Which of the following are not the lengths of the sides of a 30°-60°-90° triangle?
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Answer 1

B. 5/2, 2√3/2, 10

Explanation:

A 30-60-90 triangle must have their sides equal to x, x√3, and 2x, where x represents one of the sides.

Let's say x is 5/2, (5/2)√3 is (5√3)/2. So far this side works for a 30-60-90 triangle. But 2x would be 5/2(2) = 5.

This means the other side should be 5, not 10. Therefore this triangle cannot be a 30-60-90 triangle.

You can see that in all of the other answers, the second number is the first number times √3, and the third number is the first number times 2.