Answer:B: 36°
Step-by-step explanation:
We know that ∆ABC is isoceles, making (angle)<ABC and <BCA congruent because base angles of isoceles triangles are congruent.
Because we have parallel lines, we can look for alternate interior angle pairs. <BCA is congruent to <DAC because they're alternate interior angles.
If <BCA is x then so is <ABC.
Since triangles add up to 180° we can add all of the angles (3x+x+x) and set it equal to 180.
3x+x+x=180
5x=180
x=36
If we were looking for <BAC we would plug that back in and solve, but we're looking for <BCA which is equal to x, therefore m<BCA=36°
