You need to remember that the names of angles depend on the measures of angles, such that:

• if an angle measures less then `90^o` , the angle is called acute;
• if an angle measures exactly `90^o` , the angle is called right;
• if an angle is in `(90^o,180^o), ` the angle is called obtuse;
• if an angle measures exactly `180^o` ,the angle is called right;
• if an angle is in `(180^o,360^o), ` the angle is called reflex

Hence, since the angle measures `160^o` , then the angle is called obtuse.