Since this triangle is a right triangle and a 45 degree angle is shown, we can assume that we'll need to use the 45-45-90 relationship. Using this relationship, we know that a is equal to the hypotenuse divided by the square root of 2. Since there cannot be a radical in the denominator, we need to multiply the fraction by root 2 over root 2 (or 1) and simplify.
WORK: 28/squareroot(2) x sr(2)/sr(2) 28 sr(2) / 2 a = 14 squareroot(2)
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