Answer:
In the lower isosceles triangle diagram, angle a = 40 angle c = 40 angle b = 100 angle e = 140
Explanation:
By definition, the angles of a triangle must add up to 180. the lower angles opposite the congruent lines BE and BD must be congruent by definition of an isosceles triangle. therefore we can determine the angle b as follows... angle b = 180 - (40 x 2) = 180 - 80 = 100
Supplementary angles add up to 180 therefore, angle e = 180 - 40 = 140
Corresponding angles on parallel lines disected by a third line are congruent. Therefore, angle a = 40. As angle c is congruent to angle a, angle c must also = 40.