Answer/Step-by-step explanation:
Using α as reference angle:
Perpendicular side = BC (one of the legs that adjoins to form a right angle. It is opposite to the reference angle.)
Base side = AB (The other leg that forms a right angle with the perpendicular side at the adjoining point. It is adjacent to the reference angle)
Hypotenuse = AC (the side opposite to the right angle, 90°)
Using β as reference angle:
Perpendicular side = AB (one of the legs that adjoins to form a right angle. It is opposite to the reference angle.)
Base side = BD (The other leg that forms a right angle with the perpendicular side at the adjoining point. It is adjacent to the reference angle)
Hypotenuse = AD (the side opposite to the right angle, 90°)