Question

How do I find missing alternative angles for L2 and L3?

Answer 1

We want to find L2 and L3 angles in the figure given.

Given that:

L1 = 103.4

L4 = 76.6

Notice that L3 and L4 are supplementary angles and L1 and L2 are also supplementary angles. When two angles are supplementary angles, their sum is always 180°.

So,

$\begin{gathered} \angle1+\angle2=180 \\ 103.4+\angle2=180 \\ \angle2=180-103.4 \\ \angle2=76.6 \end{gathered}$

And,

$\begin{gathered} \angle3+\angle4=180 \\ \angle3+76.6=180 \\ \angle3=180-76.6 \\ \angle3=103.4 \end{gathered}$