Acute Angle

Equivalence angle pairs. Angles that have the same measure (i.e. the same magnitude) are said to be equal or congruent.An angle is defined by its measure and is not dependent upon the lengths of the sides of the angle (e.g. all right angles are equal in measure).

source:
en.wikipedia.org

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slideplayer.com

Complementary Angles:

In a right angled triangle, the two non-right angles are complementary, because in a triangle the three angles add to 180°, and 90° has already been taken by the right angle. When two angles add to 90°, we say they "Complement" each other.

source:
mathsisfun.com

image:
ck12.org

Obtuse Angle

Angles and Angle Pairs. ... An obtuse angle is an angle whose measure is more than 90° but less than 180°. In Figure 11 , ∠4 is obtuse. Figure 11 An obtuse angle.

source:
cliffsnotes.com

image:
slideplayer.com

Right Angle-an 90 Degree Angle

Also sometimes if we need to find the complementary of any angle, we will subtract the first angle by 90 degrees and get the complement of the given angle. So we say that the complement of 30 degree is 90 – 30 = 60 degrees. So we observe that a pair of complementary angles forms a Right Angle.

source:
math.tutorcircle.com

image:
stcaidand3h.blogspot.com

Straight Angle-a 180 Degree Angle

Straight Angle A straight angle is 180 degrees. This is a straight angle. A straight angle changes the direction to point the opposite way. Sometimes people say "You did a complete 180 on that!" ... meaning you completely changed your mind, idea or direction.

source:
mathsisfun.com

image:
sites.google.com

There are Different Types of Angle Pairs

In geometry, an angle is formed when two lines intersect at a common point. Angle pairs deals with two angles. There are different types of angle pairs. Two angles which has one line in common is called as angle pairs. In angle pairs, the two angles are related to each other.

source:
math.tutorvista.com

image:
montessoriforeveryone.com