1959 AHSME Problems/Problem 15
Problem
In a right triangle the square of the hypotenuse is equal to twice the product of the legs. One of the acute angles of the triangle is: 
Solution 1
WLOG, by scaling, that the hypotenuse has length 1. Let 
be an angle opposite from some leg. Then the two legs have length 
and 
respectively, so we have 
. From trigonometry, we know that this equation is true when 
, so our answer is 
and we are done.
Solution 2 (Answer choices)
Look at the options. Note that if 
is the correct answer, one of the acute angles of the triangle will measure to 
degrees. This implies that the other acute angle of the triangle would measure to be 
degrees, which would imply that 
is another correct answer. However, there is only one correct answer per question, so can't be a correct answer. Using a similar argument, neither 
, 
, nor can be a correct answer. Since 
is the only answer choice left and there must be one correct answer, the answer must be .
See also
| 1959 AHSC (Problems • Answer Key • Resources) | ||
| Preceded by Problem 14 |
Followed by Problem 16 | |
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