Find the value of a 6a 7a and 100​

“exterior angles of triangles. an exterior (or external) angle is the angle between one side of a triangle and the extension of an adjacent side. try this drag the orange dots on any vertex to reshape the triangle.” look to get to the answer i explained what it means and other things i hope it you .

i believe it's a.

i'm not sure on this one, most likely correct.

good luck!