The triangles in the diagram are congruent. If mF = 40°, mA = 80°, and mG = 60°, what is mB?
two triangles, abc and efg, are represented on a grid. sides ac and ge are marked congruent. sides ab and ef are marked congruent. angles a and e are marked congruent. angle b is labeled question mark.
a. 40
b. 60
c. 80
d. 100