It is known that the complementary angle of angle A and the opposite vertex angle of angle B complement each other. When a = 40 degrees, angle B =?

It is known that the complementary angle of angle A and the opposite vertex angle of angle B complement each other. When a = 40 degrees, angle B =?

When a = 40 degrees, because the opposite vertex angles are equal, so (90-40 degrees) + B = 180 degrees;
B = 130 degrees