math circle memorisation

Question 1

give me the name and rules for:
right angle in a circle

Answer 1

name: angles in a semi circle
rules:
1. 2 points MUST touch both ends of diameter
3. last point must touch circumference

Question 2

give me the rules for:
chords of a circle

Answer 2

1. perpendicular to any line
2. must touch circle centre
   a 90 angle is formed

Question 2

give me the name and rules for:
line outside circle

Answer 2

radius tangent.
- a line where only 1 point touches circumference.
- if a perp line from tangent reaches centre of circle, its a 90

Question 3

give me the description and rules for:
tangents from an external point

Answer 3

if point P is whre tangents A and B meet, it means they are equal length.

Question 4

give me the name and rules for:
2x angle

Answer 4

name: angle at the centre
- 2 angles must brunch out from same point.
- one must touch circumfrence one must touch circle centre
- the one touching circle centre is 2x

Question 5

give me the name and rules for:
butterfly!

Answer 5

name: angle subtended from the same arch
- both angles are same and the otehr 2 are same