What is the greatest number of right angles that a triangle can contain? A. 0 B. 2 C. 3 D. 1

**Answer: D. 1** A triangle is a polygon with three sides and three angles, and the sum of its interior angles always equals 180 degrees. A right angle measures 90 degrees. - **One Right Angle:** If a triangle has one right angle (90 degrees), the remaining two angles must add up to 90 degrees. For example, a 90-60-30 triangle. - **Two Right Angles:** If a triangle were to have two right angles, the sum of these angles alone would be 180 degrees, leaving no degrees remaining for the third angle. This violates the fundamental property that the sum of all three angles in a triangle must be exactly 180 degrees. - **Three Right Angles:** Similarly, having three right angles would sum up to 270 degrees, which is impossible for a triangle. Therefore, the greatest number of right angles a triangle can contain is **one**.