Login

Welcome, Guest. Please login or register.

March 29, 2024, 12:09:04 pm

Author Topic: Maths- circle geometry  (Read 1509 times)  Share 

0 Members and 1 Guest are viewing this topic.

annaconda

  • Adventurer
  • *
  • Posts: 16
  • Respect: 0
Maths- circle geometry
« on: January 31, 2017, 10:30:33 pm »
0
HI!

For this question, I know the theorem, but I don't know why you have to use the reflex angle and not the 88 degrees.


Thanks :)
HSC 2018: Eng Avd, Physics, Ext 1 Math, Ext 2 Math

RuiAce

  • ATAR Notes Lecturer
  • Honorary Moderator
  • Great Wonder of ATAR Notes
  • *******
  • Posts: 8814
  • "All models are wrong, but some are useful."
  • Respect: +2575
Re: Maths- circle geometry
« Reply #1 on: January 31, 2017, 10:50:50 pm »
0
HI!

For this question, I know the theorem, but I don't know why you have to use the reflex angle and not the 88 degrees.


Thanks :)
The angle subtended to the centre is twice the angle subtended to the circumference, on the SAME arc. So in this diagram:


The reflex angle goes to the one on the minor arc, because the major arc is the one SUBTENDING it.
The obtuse or acute angle goes to the one on the major arc, because the minor arc is the one SUBTENDING it.
« Last Edit: January 31, 2017, 10:55:04 pm by RuiAce »

annaconda

  • Adventurer
  • *
  • Posts: 16
  • Respect: 0
Re: Maths- circle geometry
« Reply #2 on: January 31, 2017, 10:55:40 pm »
0
Thanks!
HSC 2018: Eng Avd, Physics, Ext 1 Math, Ext 2 Math