1. an acute angle triangle, wrong because , one of the angles has 130° and it is more than 90°
<h2><em>2. the third angle measures is 130°,. </em><em>correct because, 20°+30°+130°=180°</em></h2>
3.2 sides have the same length, wrong
<h2>4. it is an obtuse triangle, correct because,it has (greater than 90°) and two acute angles</h2><h2><em>5. all sides have different lengths,</em><em> correct</em></h2>
6. the third angle measures 50°, wrong because, 20+30+50=100 and 100 is not the sum of triangle angles.
Obtuse triangle is a triangle that has one angle that is more than 90 degrees and all the sides have different lengths since all the angles are different.