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Geometry Triangle Angle : 2

Introduction to geometry angle triangle:

Atriangle consists of three points which can be joined to form a shape of figure. The three line segments are joined to form the triangle. A triangle can be built when its sides are given or when its angles are given and any two angles or sides are given etc. Here we are going to see about the geometry angle triangle.

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Types of angle on geometry triangle angle

Acute angle:

Acute angle is nothing but the angle which measures less than 90°. Example: 50°, 67° etc.

Obtuse angle:

The obtuse angle measures greater than 90° and less than 180°. Some of the angles for example are 120°, 148° etc.

Right angle:

The right angle which consists of 90° in a triangle.

  • In a triangle there are different names given according to their size of angles and sides of its measurements.

  • The opposite side of the angle is the greatest angle of the triangle.

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Example problems on geometry triangle angle

Ex 1:

Determine the third angle in a triangle where the other two angles are 50°, 60°.


The sum of the three angles in a triangle measures 180°

50° + 60° + x° = 180°

x° = 180° - 110°

= 70°

Thus the x° = 70° is the third angle of the triangle.

Ex 2:

Determine the acute angle measurement of the triangle measurement of one of the angle of a triangle is 50°.


The addition of the two acute angles equals to 90°.

In a right angle triangle the angle given is 50°, and then the measure of the other angle is 90° - 50° = 40 °

Ex 3:

Determine the third angle in a right angle triangle where the angle is 60°. Find the third angle.


In a triangle, the right angle which measures about 90°.

Thus we can find the third angle by subtracting the other two angles from 180°.

60° + 90° + x° = 180°

x° = 180° - 150°

x° = 30°

The third angle of the given right angle triangle is 30°