A3. Which triplet of numbers represents the sides of a right triangle?
(A) $(3,4,6)$
(B) $\left(1, \frac{1}{4}, \frac{15}{16}\right)$
(C) $(14,49,50)$
(D) $\left(\frac{3}{4}, 1,1 \frac{1}{4}\right)$
(E) $(6,7,8)$
A3. The Pythagorean theorem holds for the triplet of numbers $\left(\frac{3}{4}, 1,1 \frac{1}{4}\right)$, because $\left(1 \frac{1}{4}\right)^{2}=1^{2}+\left(\frac{3}{4}\right)^{2}$. For other triplets of numbers, the Pythagorean theorem does not hold.