 Hello and welcome to the session. In this session we discussed the following question which says give reasons for the following. First, a triangle cannot have two right angles. Second, a triangle cannot have two obtuse angles. Before we state the reasons for the given two parts of the question, let's recall the angles some property of or triangle. According to this we have the sum of the angles of a triangle is 180 degrees. This is the key idea to be used in this question. Let's see the solution now. First we have that a triangle cannot have two right angles. Now, if a triangle has two right angles, that is if a triangle has two angles of 90 degree measure, then the sum of three angles for triangle would be more than 180 degrees, which is not possible since we know that the sum of the angles of a triangle is 180 degrees. So this is the reason why a triangle cannot have more than one right angle or a triangle cannot have two right angles. Now, the second part of the question is a triangle cannot have two obtuse angles. Now we know obtuse angle means angle of measure more than 90 degrees. Now, consider a triangle two angles measuring 100 degrees and 120 degrees, that is they are the obtuse angles. Now, the sum of the given two angles of measure 100 degrees and 120 degrees is 220 degrees, which is more than 180 degrees. This is not possible since we know that the sum of the three angles of a triangle is 180 degrees. Therefore, a triangle cannot have two obtuse angles. So this completes the session. Hope you have understood the solution of this question.