Triangle Fundamentals

Front

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

Back

The smallest angle is opposite the smallest side, and the largest angle is opposite the largest side.

Front

Can a triangle have sides of lengths 3, 4, and 9?

Back

No, because the sum of the lengths of the two shorter sides (3 + 4 = 7) must be greater than the length of the longest side (9).

Front

How do you order angles in a triangle from greatest to least?

Back

Order the angles based on the lengths of the opposite sides; the largest angle is opposite the longest side.

Front

What is the sum of the angles in a triangle?

Back

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

Front

If angle a + angle b = angle d, what can you conclude?

Back

Angle d is equal to the sum of angles a and b.

Front

What is the measure of an angle if the other two angles in a triangle are 70 degrees and 50 degrees?

Back

The measure of the third angle is 60 degrees (180 - 70 - 50 = 60).

Front

What is the definition of an isosceles triangle?

Back

An isosceles triangle has at least two sides that are equal in length.

Front

What is the definition of a scalene triangle?

Back

A scalene triangle has all sides of different lengths.

Front

What is the definition of an equilateral triangle?

Back

An equilateral triangle has all three sides equal and all angles measuring 60 degrees.

Front

What is the Pythagorean theorem?

Back

In a right triangle, the square of the length of the hypotenuse is equal to the sum of the squares of the lengths of the other two sides (a² + b² = c²).