You would classify the triangle as a Right triangle. You would classify it as a Right Triangle because the total amount of degrees in a triangle must be 180 degrees. If you add 42 and 48, it would give you 90 degrees. 180 - 90 degrees would equal 90 degrees. Meaning, the final corner would be 90 degrees. If 1 corner of a triangle is 90 degrees, it would classify as a right triangle.