Understanding Triangles

This video tutorial introduces triangles, explaining their basic properties, such as having three sides, vertices, and angles. It covers the classification of triangles based on angles (acute, right, obtuse) and sides (isosceles, scalene, equilateral). The video also discusses key properties, including the sum of internal angles being 180 degrees and external angles being 360 degrees. These concepts are applied in exercises to reinforce understanding.

What is a triangle?

• A figure with three sides

• A figure with four sides

• A figure with six sides

• A figure with five sides

How many vertices does a triangle have?

• Four

• Two

• Three

• Five

What is a characteristic of an acute triangle?

• It has one angle greater than 90 degrees

• It has one angle equal to 90 degrees

• All angles are less than 90 degrees

• All angles are equal to 60 degrees

Which type of triangle has one angle equal to 90 degrees?

• Acute triangle

• Right triangle

• Obtuse triangle

• Equilateral triangle

What defines an obtuse triangle?

• All angles are less than 90 degrees

• It has one angle equal to 90 degrees

• It has one angle greater than 90 degrees

• All angles are equal to 60 degrees

What is true about an isosceles triangle?

• It has all sides of different lengths

• It has two sides of equal length

• It has all sides of equal length

• It has one angle equal to 90 degrees

Which triangle has all sides of different lengths?

• Right triangle

• Scalene triangle

• Isosceles triangle

• Equilateral triangle

What is a property of an equilateral triangle?

• It has two sides of equal length

• All sides and angles are equal

• It has one angle greater than 90 degrees

• It has one angle equal to 90 degrees

What is the sum of the internal angles of any triangle?

• 360 degrees

• 90 degrees

• 180 degrees

• 270 degrees

What is the sum of the external angles of any triangle?

• 270 degrees

• 360 degrees

• 90 degrees

• 180 degrees