CIRCLE RULES

Folie 1

• 
• isos ▵, = radii, base angles =

Folie 2

• 
• angle at center is 2x angle at circumf

Folie 3

• 
• angles on same arc are =

Folie 4

• 
• cyc quad, opp angles add to 180
• *cyclic quadrilateral has all 4 points touching the circumf

Folie 5

• 
• cyc quad, ext angle = int opp angle

Folie 6

• 
• tangent to radi = 90 degrees

Folie 7

• 
• = tgts
• (AT = BT)

Folie 8

• 
• isos ▵, = tgts

Folie 9

• 
• angle between tgt and chord = angle on chord in opp segment

Folie 10

• 
• angle in a semi-circle is 90 degrees