Understanding Triangles

This video tutorial covers the classification of triangles by angles and sides, including acute, right, obtuse, scalene, isosceles, and equilateral triangles. It explains the triangle angle sum theorem, demonstrating that the sum of angles in a triangle is always 180 degrees. The video includes exercises for classifying triangles and solving for unknown angles, as well as a word problem involving angle ratios. The tutorial concludes with a summary and directs viewers to additional resources for further learning.

Which type of triangle has all angles less than 90 degrees?

• Right triangle

• Scalene triangle

• Obtuse triangle

• Acute triangle

What is a triangle called if it has one angle exactly equal to 90 degrees?

• Obtuse triangle

• Equilateral triangle

• Right triangle

• Acute triangle

Which triangle has no sides of equal length?

• Equilateral triangle

• Isosceles triangle

• Right triangle

• Scalene triangle

In an equilateral triangle, what is the measure of each angle?

• 45 degrees

• 60 degrees

• 90 degrees

• 120 degrees

If a triangle has two sides of equal length, what is it called?

• Scalene triangle

• Isosceles triangle

• Right triangle

• Equilateral triangle

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

• 360 degrees

• 270 degrees

• 180 degrees

• 90 degrees

If two angles of a triangle are 54° and 38°, what is the third angle?

• 84 degrees

• 98 degrees

• 92 degrees

• 88 degrees

In a triangle, if angle A is 35°, angle B is 4x, and angle C is 3x + 7, what is the value of angle B?

• 45 degrees

• 60 degrees

• 50 degrees

• 55 degrees

If the angles in a triangle are in the ratio 4:5:11, what is the measure of the largest angle?

• 36 degrees

• 45 degrees

• 72 degrees

• 99 degrees

What is the measure of angle A if the angles in a triangle are in the ratio 4:5:11?

• 63 degrees

• 45 degrees

• 36 degrees

• 54 degrees