6.8A Triangle Sides and Angles

Front

What is a triangle?

Back

A triangle is a polygon with three edges and three vertices. It is one of the basic shapes in geometry.

Front

What are the types of triangles based on side lengths?

Back

1. Equilateral Triangle: All sides are equal. 2. Isosceles Triangle: Two sides are equal. 3. Scalene Triangle: All sides are different.

Front

What are the types of triangles based on angles?

Back

1. Acute Triangle: All angles are less than 90 degrees. 2. Right Triangle: One angle is exactly 90 degrees. 3. Obtuse Triangle: One angle is greater than 90 degrees.

Front

What is the Triangle Inequality Theorem?

Back

The sum of the lengths of any two sides of a triangle must be greater than the length of the third side.

Front

If a triangle has sides of lengths 15, 12, and 9, does it exist?

Back

Yes, it satisfies the Triangle Inequality Theorem.

Front

How do you order the angles of a triangle from largest to smallest?

Back

The largest angle is opposite the longest side, the second largest angle is opposite the second longest side, and the smallest angle is opposite the shortest side.

Front

In triangle XYZ, if angle X = 83° and angle Y = 68°, what is the measure of angle Z?

Back

Angle Z = 29° (because the sum of angles in a triangle is 180°).

Front

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

Back

The sum of the interior angles of a triangle is always 180 degrees.

Front

If one angle of a triangle is 58°, what is the measure of the third angle if the second angle is 64°?

Back

The third angle = 180° - 58° - 64° = 58°.

Front

Which set of side lengths cannot form a triangle? {2, 5, 9}, {3, 4, 5}, {5, 10, 12}, {7, 9, 11}

Back

{2, 5, 9} cannot form a triangle because 2 + 5 is not greater than 9.