F, E and D are exterior angles.
Exterior angles and corresponding interior angles are suppementary (they add up to 180°)
Use F to find the meaure of C:
[tex]\begin{gathered} F+C=180 \\ C=180-F \\ C=180-110 \\ C=70 \end{gathered}[/tex]
Use E to find the measure of B:
[tex]\begin{gathered} E+B=180 \\ B=180-E \\ B=180-100 \\ B=80 \end{gathered}[/tex]
The sum of the interiror angles of any triangle is 180°.
Use B and C to find the meaure of A:
[tex]\begin{gathered} A+B+C=180 \\ A=180-B-C \\ A=180-80-70 \\ A=30 \end{gathered}[/tex]
Use A to find the meaure of D:
[tex]\begin{gathered} A+D=180 \\ D=180-A \\ D=180-30 \\ D=150 \end{gathered}[/tex]Then, the measure of angle D is 150°
