Basic Facts of Triangles

Find b.

Find the measure of the missing angle in the triangle.

Find the measure of the missing angle in the triangle.

An obtuse triangle has (a)   ​

• one obtuse angle

• three obtuse angles

• one acute angle

• the sum of a triangles 3 angles.

• the sum of a triangles 3 sides

• the area of a triangle

• the distance around a triangle

A ​ (a)   triangle has ​ (b)   right angle,

• right

• one

• obtuse

• scalene

• two

• three

• acute

A ​ (a)   triangle has ​ (b)   right angle.

• right

• one

• obtuse

• scalene

• two

• three

• acute

Use the angles to classify the triangles

all angles less than 90° - acute triangle

1 angle is equal to 90° - right triangle

1 angle is greater than 90° - obtuse triangle

Use the sides to identify the triangle

0 sides the same - scalene triangle

2 sides the same - isosceles triangle

3 sides the same - equilateral triangle

Use the sides to identify the triangle

0 sides the same - scalene triangle

2 sides the same - isosceles triangle

3 sides the same - equilateral triangle