A scalene triangle with all angles less than 90° is an acute-angled triangle. A scalene triangle with angles of 50°, 60° and 70° is an acute-angled triangle.

Acute angle triangle has all of its angles less than 90° in measure. Rectangle: It is a four sided polygon with opposite sides equal to each other and the sum of all of its angles is equal to 360°.

It categorizes triangles into equilateral, isosceles, scalene, obtuse, right, and acute based on their sides and angles. The video also covers the concept of congruency, demonstrating how two ...