CLASSIFYING TRIANGLES BASED ON ANGLES MEASURES

On the basis measurement of the angles, triangles are classified into three categories.

• Acute Angle Triangle
• Right Angle Triangle
• Obtuse Angle Triangle

Acute Angle Triangle :

If all the angles of the triangle are less than  90˚, then the triangle is classified as an Acute Angle Triangle.

Right Angle Triangle :

If one of the angles is 90˚, then the triangle is classified as a Right Angle Triangle.

Obtuse Angle Triangle :

If one of the angles is greater than 90˚, then the triangle is classified as an Obtuse Angle Triangle.

Classify the following triangles by its angle measure.

Problem 1 :

Solution :

By observing the figure,

<A = 71˚, <B =  71˚, and, <C =  38˚

Since all the angles are less than 90˚, it is an

Acute Angle Triangle

Problem 2 :

Solution :

By observing the figure,

<A = 42˚, <B =  90˚, and, <C =  48˚

Since <B is 90˚, it is a

Right Angle Triangle

Problem 3 :

Solution :

By observing the figure,

<A = 40˚, <B =  40˚, and, <C =  100˚

Since <C is greater than 90˚, it is an

Obtuse Angle Triangle

Problem 4 :

Solution :

By observing the figure,

<A = 90˚, <B =  50˚, and, <C =  40˚

Since <A is 90˚, it is a

Right Angle Triangle

Problem 5 :

Solution :

By observing the figure,

<A = 87˚, <B =  55˚, and, <C =  38˚

Since all the angles are less than 90˚, it is an

Acute Angle Triangle

Problem 6 :

Solution :

By observing the figure,

<A = 15˚, <B =  135˚, and, <C =  30˚

Since <B is greater than 90˚, it is an

Obtuse Angle Triangle