How to classify polygons by the measure of their angles

The video tutorial covers the classification of triangles based on their angles. It explains acute triangles, including those with equal angles, obtuse triangles, and right triangles. The teacher emphasizes the properties and limitations of each type, such as the impossibility of having more than one obtuse angle in a triangle. The importance of right triangles and their use in the Pythagorean theorem is highlighted.

What is the defining characteristic of an acute triangle?

• One angle is exactly 90 degrees.

• All angles are less than 90 degrees.

• All angles are equal.

• One angle is more than 90 degrees.

What do we call a triangle with three equal acute angles?

• Scalene triangle

• Right triangle

• Isosceles triangle

• Equilateral triangle

Why can't a triangle have more than one obtuse angle?

• Because the sum of angles in a triangle is 180 degrees.

• Because obtuse angles are more than 180 degrees.

• Because obtuse angles are less than 90 degrees.

• Because obtuse angles are equal to 90 degrees.

What is the sum of all interior angles in a triangle?

• 270 degrees

• 360 degrees

• 90 degrees

• 180 degrees

What is a triangle with one angle exactly 90 degrees called?

• Equilateral triangle

• Right triangle

• Obtuse triangle

• Acute triangle

Which theorem is applicable only to right triangles?

• Cosine rule

• Triangle inequality theorem

• Sine rule

• Pythagorean theorem

What symbol indicates a right angle in a triangle diagram?

• A triangle

• A square box

• A small circle

• A tick mark