angles

angles are divide into 7 kinds is acute angle, right angle, obtuse angle, straight angle, reflex angle, zero angle and complete angle.

acute angle

the acute angle was smaller than 90 degrees but bigger than 0 degrees.

right angle

an angle that exactly 90 degrees.

Obtuse angle

an angle that bigger than 90 degrees but smaller than 180 degrees.

straight angle

the angle that exactly 180 degrees.

reflex angle

the angle's degrees is bigger than 180 degrees but smaller than 360 degrees

zero angle

the angle exactly 0 degrees

complete angle

the angle that exactly 360 degrees

Review

acute angle smaller than 90 degrees but bigger than 0. Right angle exactly 90 degrees.Obtuse angle bigger than 90 degrees but smaller than 180 degrees.Straight angle are exactly 180 degrees.Reflex angle bigger than 180 degrees but smaller than 360 degrees. Zero angle are exactly 0 degrees.Complete angle are exactly 360 degrees.