Answer:
See attached. ∠A is a right angle, ∠B and ∠D are acute, ∠C is obtuse.
Explanation:
A right angle is defined as an angle equal to 90 degrees.
An acute angle is defined as an angle less than 90 degrees.
An obtuse angle is defined as an angle greater than 90 degrees.
Using this information we will classify all of the four given angles.
∠A is a right angle, 90 = 90
∠B is acute angle, 60 < 90
∠C is obtuse angle, 160 > 90
∠D is acute angle, 70 < 90