Triangle Inequality

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

List the conditions for three lengths to form a triangle.

Back

For three lengths a, b, and c to form a triangle, the following must be true: a + b > c, a + c > b, and b + c > a.

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 degrees).

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.

Front

What is an acute triangle?

Back

An acute triangle is a triangle in which all three angles are less than 90 degrees.

Front

What is an obtuse triangle?

Back

An obtuse triangle is a triangle that has one angle greater than 90 degrees.

Front

If the sides of a triangle are 4 cm, 7 cm, and 10 cm, can they form a triangle?

Back

Yes, they can form a triangle because 4 + 7 > 10, 4 + 10 > 7, and 7 + 10 > 4.

Front

Which of the following lengths cannot represent the sides of a triangle: 2, 4, 5, 12?

Back

12 cannot represent the sides of a triangle because 2 + 4 = 6, which is not greater than 12.

Front

Identify the longest side in a triangle with sides 5 cm, 12 cm, and 13 cm.

Back

The longest side is 13 cm.

Front

What is the relationship between the sides of a triangle and its angles?

Back

In a triangle, the largest angle is opposite the longest side, and the smallest angle is opposite the shortest side.