In a triangle when we refer to an angle, we mean the angle bounded by the two sides. The three angles lie in the interior region of the triangle. These angles are called the interior angles of the triangle. Now observe the triangle in which the sides are produced.
As the triangle has three sides, there can be three exterior angles. The interior angles opposite to the vertex where the exterior angle is formed, are called the interior opposite angles. Thus in the figure, exterior angle OXZ is formed at X. Its interior opposite angles are
In the adjoining figure,
Activity:
Complete the following table by measuring the interior and exterior angles of the figure given above using a protractor.
Study the table carefully and identify the relation between exterior and interior opposite angles.
Complete the following table by measuring the interior and exterior angles of the figure given above using a protractor.
Study the table carefully and identify the relation between exterior and interior opposite angles.
