chapt 2.1 & 2.2 - angles , triangles , polygons , Con and Sim

Question 1

types of angles

Answer 1

1) x < 90° = acute angle
2) x = 90° = right angle
3) 90° < x < 180° : obtuse angle
4) 180° < x < 360° : reflex angle

5) complementary angles
- angle x + angle y = 90°

6) supplementary angles
- sum of 2 angles = 180°

Question 2

angle properties

Answer 2

1) adj. angles on a st. line = 180°
2) angles at a point = 360°
3) vert opp angles
4) alt angles , __ // __
5) sum of angles in a triangle = 180°

Question 3

polygon formulas (n-sides)

Answer 3

1) interior angles
- (n - 2) x 180° -> sum of angles
- [(n - 2) x 180°] / 2 -> each angles

2) exterior angles
- 360° -> sum of angles
- 360°/ n -> each angle

Question 4

congruence properties

Answer 4

1) SSS property
- if both triangles share equal sides

2) SAS property
- an angle between 2 sides that share equal sides

3) ASA property
- a side between 2 angles

4) AAS property
- 2 angles and a side

5) RHS property
- the only property with right angle

Question 5

similarity properties

Answer 5

• are similar if corresponding sides and angles are proportional and equal respectively

1) AA similarity
- when 2 angles are equal in both triangles
- not need to find the 3rd angle because sum of triangle = 180°

2) SSS similarity
- if sides are proportionate

3) SAS similarity
- if 2 sides are proportionate and between theres an angle

Question 6

factors and solids

Answer 6

1) scale factor = length of image / length of object

2) similar plane figures
- ratio of corresponding sides of 2 similar figures

e. g;
- ℓ1 : ℓ2
- ℓ² 1 : ℓ² 2 ( area )
- ℓ³ 1 : ℓ³ 2 ( volume )

(3) and (4) refer to notes