Angle One

An angle is formed by rays that share an endpoint.

Look at this angle:

 

                     

The angle one is form by line AC and AT . Point A is the angle vertex. Point S is the interior point, because S is inside the angle. Point H is exterior point, because H is outside the angle. The angle is named angle A or  angle TAC or angle CAT or  just angle one.

See the angels

 

                    Measure of angle YAP is 60 ̊  and measure of angel DOG is also 60 ̊ .

Angle YAP and DOG are congruent.

m<YAP =᷉  m<DOG

Angle YAP and angle DOG are call a cute angles. A cute angles is measure less than 90 ̊ .

                    A right angle is measure exactly ninety degree. The obtuse angle is measure more than ninety degree, but it’s less than one hundred eighty degree. A stright angle measure exactly one hundred eighty degree. The straight angle is just like a straight line.

Adjecent Angles

Adjecent angles are coplanar angles that share common vertex and common side.

 

no common interior points

Complementary Angles

                    Look at the complementary angels. Complementary angles are two angles whose measures add up to 90 degrees. It is like angle y and angle O

 

               The measures of angle O is 33 ̊ and the measures of angle Y is 57 ̊. If we add the measure of  angle O and angle Y, we get 90 ̊ . So, angle O and angle Y are a complementary angles.

Suplementary Angles

               Suplementary angles is two angles whose measures add up to 180 ̊ , like angle A and angle D:

 

                  Angle A is ninety nine degrees and angle D is eighty one degrees. So, angle A and angle D are suplementary angles.

The Complementary and Suplementary angles do not by adjacent.

Vertical Angles

                  Vertical angles are two angles that occur opposite each other when two lines are intersect.

                                                                                                                < 1 = < 2

                                                                                                                <3= <4

                  Angle  one is congruent with angle two and angle three is congruent with angle four because it’s vertical angles.

for example:

                                                                                          

Because angle one and angle two is vertical angles, so angle two is 55 ̊ .  Angle one and four is 180 ̊ , it’s stright angle, so

m< 1 + m< 4 = 180 ̊

55 ̊  + m< 4 = 180 ̊

m<4= 180 ̊  - 55 ̊ = 125 ̊

Because angle four and angle 2 is vertical angle, so the measure of angle 2 is also 125 ̊ .

Angle Bisector

          Angle bisector is a ray that splits an angle, forming two congruent adjacent angles.

Here line QR is bisect <SQT. So, from the definition, we can conclude that <SQR and < QTR are congruent.

Perpendicular Lines

Perpendicular lines are intersecting lines that form right angles. It can write by  symbol “ ┴”.

                                                                                               

  This perpendicular line is formed by line             l and line m, so l    m.