6.8A Triangle Sides and Angles

Front

Can the following side measures form a triangle? 3, 5, 8

Back

No, because the sum of the lengths of the two shorter sides (3 + 5 = 8) is not greater than the length of the longest side (8).

Front

Which of the following does not represent the lengths of the sides of a triangle? 2 cm, 6 cm, 7 cm, 5 cm, 2 cm, 5 cm, 5 cm, 5 cm, 8 cm, 3 cm, 10 cm, 15 cm

Back

3 cm, 10 cm, 15 cm do not satisfy the triangle inequality theorem.

Front

Find the measure of the missing angle if the other two angles are 62° and 60°.

Back

The missing angle is 58°, because the sum of angles in a triangle is 180° (180° - 62° - 60° = 58°).

Front

Does a triangle with these side lengths exist? 15, 12, 9

Back

Yes, because the sum of the lengths of any two sides (15 + 12 > 9, 15 + 9 > 12, 12 + 9 > 15) is greater than the length of the third side.

Front

Which side lengths would NOT form a triangle? {3,4,5}, {2,5,9}, {5,10,12}, {7,9,11}

Back

{2,5,9} do not satisfy the triangle inequality theorem.

Front

What is the Triangle Inequality Theorem?

Back

The Triangle Inequality Theorem states that the sum of the lengths of any two sides of a triangle must be greater than the length of the third side.

Front

If one angle of a triangle is 90°, what type of triangle is it?

Back

It is a right triangle.

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°.

Front

What is an equilateral triangle?

Back

An equilateral triangle is a triangle in which all three sides are of equal length and all three angles are equal (each measuring 60°).

Front

What is an isosceles triangle?

Back

An isosceles triangle is a triangle that has at least two sides of equal length and the angles opposite those sides are equal.