angles

Definition of angle: 

angle

noun

plural noun: angles

1. 1.

   the space (usually measured in degrees) between two intersecting lines or surfaces at or close to the point where they meet.

   
   

   "in any triangle, the longest side is opposite the largest angle"

   • a corner, especially an external projection or an internal recess of a part of a building or other structure.

     
     

     "a skylight in the angle of the roof"

     
     

     synonyms:

     corner, intersection, point, apex, cusp; More

   • a measure of the inclination of one line or surface with respect to another.

     
     

     "sloping at an angle of 33° to the horizontal"

     
     

     synonyms:

     gradient, slant, inclination; geometrical relation "the wall is sloping at an angle of 33° to the vertical"

   • a position from which something is viewed or along which it travels or acts, typically as measured by its inclination from an implicit horizontal or vertical baseline.

     
     

     "from this angle Maggie could not see Naomi's face"
2. 2.

   a particular way of approaching or considering an issue or problem.

   
   

   "discussing the problems from every conceivable angle"

   
   

   synonyms:

   perspective, way of looking at something, point of view, viewpoint, standpoint,position, side, aspect, slant, direction, approach, outlook, light "we need to consider the problem from a different angle"

In planar geometry, an angle is the figure formed by two rays, called the sides of the angle, sharing a common endpoint, called the vertex of the angle. Angles formed by two rays lie in a plane, but this plane does not have to be a Euclidean plane.

• Angles smaller than a right angle (less than 90°) are called acute angles ("acute" meaning "sharp").
• An angle equal to 1/4 turn (90° or π/2 radians) is called a right angle. Two lines that form a right angle are said to be normal, orthogonal, or perpendicular.
• Angles larger than a right angle and smaller than a straight angle (between 90° and 180°) are called obtuse angles ("obtuse" meaning "blunt").
• An angle equal to 1/2 turn (180° or π radians) is called a straight angle.
• Angles larger than a straight angle but less than 1 turn (between 180° and 360°) are called reflex angles.
• An angle equal to 1 turn (360° or 2π radians) is called a full angle, complete angle, or a perigon.
• Angles that are not right angles or a multiple of a right angle are called oblique angles.

As the Angle Increases, the Name Changes:

https://www.mathsisfun.com/angles.html

Be Careful What You Measure

This is an Obtuse Angle	And this is a Reflex Angle
But the lines are the same ... so when naming the angles make sure that you know which angle is being asked for!

Positive and Negative Angles

When measuring from a line:

• a positive angle goes counterclockwise (opposite direction that clocks go)
• a negative angle goes clockwise

Example: −67°

 

Parts of an Angle

The corner point of an angle is called the vertex

And the two straight sides are called arms

The angle is the amount of turn between each arm.

How to Label Angles

There are two main ways to label angles: 1. give the angle a name, usually a lower-case letter like a or b, or sometimes a Greek letter like α (alpha) or θ (theta) 2. or by the three letters on the shape that define the angle, with the middle letter being where the angle actually is (its vertex). Example angle "a" is "BAC", and angle "θ" is "BCD" https://www.mathsisfun.com/angles.html How To Name Angles: We name angles in three different ways: (1) We can name angles by using THREE capital letters like: ABC or DEF. The middle letter is called the VERTEX of the angle. The above angles are read "angle ABC" and "angle DEF." more coming soon sources  https://www.mathsisfun.com/angles.html