So ∠ A+∠ B = 180 (two lines are parallel and complementary angles of each other).

Because ∠ a = 60.

So ∠ B = 180-∠ A = 120.

You can't find the degree of ∠D without measuring it.

3. The first question ∠ 2 = 1 10 Because two straight lines are parallel, the internal dislocation angles are equal.

The second question ∠ 3 = 1 10 because two straight lines are parallel and equal to the complementary angle.

The third question ∠ 4 = 70 because two straight lines are parallel and complementary.