In a right-angled triangle, the measure of one angle is $55^{\circ}$. The measure of the smallest angle in this triangle is
(A) $1^{\circ}$
(B) $25^{\circ}$
(C) $45^{\circ}$
(D) $35^{\circ}$
(E) $90^{\circ}$
The measure of the three angles in any triangle add to $180^{\circ}$.

Since two of the angles measure $90^{\circ}$ and $55^{\circ}$, then the third angle in the triangle measures $180^{\circ}-90^{\circ}-55^{\circ}=35^{\circ}$.

The measure of the smallest angle in the triangle is $35^{\circ}$.

ANSWER: (D)