hello
from the question given, we can easily find the value of angle 5
[tex]\begin{gathered} \measuredangle5=180-\measuredangle6 \\ reason\colon\text{ angle on a straight line is equal to 180 degre}e \\ \measuredangle5=180-76 \\ \measuredangle5=104^0 \end{gathered}[/tex]
having found the value of angle 5, it is easily relatable to angle 3 because they are alternating angles to each other
[tex]\begin{gathered} \measuredangle5=\measuredangle3 \\ \text{alternating angles are equal} \\ \measuredangle5=104^0 \\ \measuredangle3=104^0 \end{gathered}[/tex]
from the calculations above, the value of angle 3 is equal to 104 degrees
it is an alternate interior angle theorem
