<span>A </span>regular triangle<span> is one for which all </span>sides<span> are </span>congruent<span> and all </span>interior angles<span> are congruent, the sum of the interior angles are always 180°, so 180 : 3 = 60°
60°</span>
Since it is a right angle you would subtract 57 from 90 because both angles added together are 90°. 90-57= 33°