Advertisement
banner image
Print

Maths

Circles - Higher

Page:

  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9
  10. 10
  1. Back
  2. Next

Opposite angles in a cyclic quadrilateral add up to 180°

A cyclic quadrilateral is a quadrilateral whose vertices all touch the circumference of a circle. The opposite angles add up to 180o.

In the cyclic quadrilateral below, angles A + C = 180o, and angles B + D = 180o.

image: circle with a quadrilateral shape inside: top corner: A, right: B, bottom: C, left: D.

Question

What is the size of:

  1. angle A?
  2. angle B?
image: circle with a quadrilateral shape inside: top corner: B, upper right: A, lower right: 140 degrees, bottom: 60 degrees.

toggle answer

Answer
  1. A + 60° = 180°, so A = 120°.
  2. B + 140° = 180°, so B = 40°.

Page:

  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9
  10. 10
  1. Back
  2. Next
 

Back to Shape, space and measures index

Chat

boy smiling

Maths Message Board

Post ideas and discuss Maths here.

Activity

maths activity

Transformation

No robots in disguise, but this activity will transform your revision!

Links

Skillswise

Skillswise

Make sure your maths skills add up.

On bbc.co.uk

On the web

Explore the BBC

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.