Two angles in a triangle measure [tex]$102^{\circ}$[/tex] and [tex]$67^{\circ}$[/tex]. What is the measure of the third angle?

A. [tex][tex]$11^{\circ}$[/tex][/tex]
B. [tex]$78^{\circ}$[/tex]
C. [tex]$113^{\circ}$[/tex]
D. [tex][tex]$169^{\circ}$[/tex][/tex]



Answer :

To solve for the measure of the third angle in a triangle where the other two angles are given, we need to use the fundamental property of triangles: the sum of the interior angles of any triangle is always [tex]\( 180^\circ \)[/tex].

Given:
- First angle, [tex]\( \angle1 = 102^\circ \)[/tex]
- Second angle, [tex]\( \angle2 = 67^\circ \)[/tex]

Step-by-step solution:

1. Add the measures of the two given angles:
[tex]\[ \angle1 + \angle2 = 102^\circ + 67^\circ \][/tex]

2. Calculate the sum:
[tex]\[ 102^\circ + 67^\circ = 169^\circ \][/tex]

3. Subtract this sum from the total measure of the interior angles of a triangle, [tex]\( 180^\circ \)[/tex]:
[tex]\[ \text{Third angle} = 180^\circ - 169^\circ \][/tex]

4. Perform the subtraction:
[tex]\[ 180^\circ - 169^\circ = 11^\circ \][/tex]

Therefore, the measure of the third angle is [tex]\( 11^\circ \)[/tex].

So, the correct answer is [tex]\( 11^\circ \)[/tex].