A scalene triangle with one angle greater than 90° is an obtuse-angled triangle. A scalene triangle with angles of 100°, 20° and 60° is an obtuse-angled triangle.

Discusses the properties and types of triangles, explaining that a triangle is a closed figure with three sides and angles. It categorizes triangles into equilateral, isosceles, scalene, obtuse ...

Because if the triangle will have two obtuse angles (angles greater than 90°), then the sum of all three angles of the triangle will not be equal to 180°, it will be more than 180°. 4.