What are Circle Theorems- Help with IGCSE GCSE Maths

Follow Maths

Are you following me on Facebook yet? Follow the link, like me on Facebook and be the first one to receive important news and updates.

follow explaining maths on facebook and pass your next maths exam!

What are Circle Theorems

On your IGCSE GCSE Maths exam you will not only have to calculate angles in polygons, you will also have to be able to find angles in circles. This section will explain the various Circle Theorems to you. Many students are intimidated by the Circle Theorems and think they are difficult to understand. However, if you know what you should be looking for you will notice that questions about Circle Theorems are actually quite easy and even fun! Therefore you need to study all the following maths videos and example questions carefully during your maths revision. You will get questions on Circle Theorems on your maths exam so make sure to study them now. Good luck and have fun!

How to find Angles at the Centre of a Circle - Help with Circle Theorems

Watch the next maths video and learn how to find angles at the centre of a circle. You will understand what is meant with this Circle Theorem and what to look for to be able to apply the theorem. Usually you will have to use this Circle Theorem if you see an arrow in a Circle made out of 2 radii and another point on the circumference with lines towards the ends of the two radii (you will understand what I am saying when watching my video). The angle at the centre of the circle will be twice as large as the angle at the circumference. Check the example question at the end of the video and understand this Circle Theorem.

How to find Angles in a Semicircle - Help with Circle Theorems

The following maths activity will explain to you the angles in a semicircle. You will understand that this is not a new or separate circle theorem, but the same as angles at the center of a circle. Many times angles in a semicircle appear on an IGCSE GCSE exam. Whenever in a question about circle theorems it states that a particular line is the DIAMETER of the circle, then you will be dealing with angles in a semicircle. It will mean that the angle opposite of the diameter is 90 degrees (half of 180 degrees, angles on a straight line). So you will have a right-angled triangle and therefore can be asked to do some Trigonometry and apply Pythagoras' Theorem. In the next video you will learn exactly what is meant with angles in a semicircle.

How to find Angles in the same Segment - Help with Circle Theorems

Learn how to find angles is in the same segment when solving questions involving circle theorems. You will understand that for this theorem you will be looking for a bow tie in a circle. The angles in the same segment will be equal in size. Study the next video about angles in the same segment during your maths revision and check out the example question. Then you will arrive well prepared at your next IGCSE GCSE maths exam. Let me know on the forum of this site if you still don't understand and I will explain Circle Theorems again to you by making some more videos. Good luck and have fun! Good luck!

What is a Cyclic Quadrilateral - Explaining Circle Theorems

The next video will explain to you what a Cyclic Quadrilateral is and what its properties are. You will understand that a cyclic quadrilateral is a quadrilateral which has all its four vertices on the circumference of a circle. Important about cyclic quadrilaterals is that the sum of opposite angles always equals to 180 degrees. Have a look at the next maths example question explaining cyclic quadrilaterals and pass your next maths exam. Have fun!

What is the Angle between a Tangent and the Radius and Length of Tangents from an External Point

Finally you need to know some properties about tangents to a circle. A tangent to a circle is a line just touching the circumference of the circle at 1 point. The video will explain that the angle between the radius and tangent will always be 90 degrees (a perpendicular angle). Another important property about tangents and circles is that 2 tangents from 1 external point to the circumference of the circle will always be equal in length. As a result questions on your IGCSE GCSE maths exam involving circles and tangents will also involve kites. Have a look at the next video what I exactly mean with that. Let me know on the forum of this website if you still don't understand circle theorems and I will help you with your maths. Good luck and have fun!

Solve Past Paper Question about Trigonometry, Circle Theorems and Arc length

A students asked me to help with this past maths exam question. The question comes from a past IGCSE paper. I will explain to you how to use trigonometry, circle theorems and our understanding of how to calculate the length of an arc in order to answer this question. I hope it will be useful during your maths revision!

Congratulations! You now understand what circle theorems are which is an important topic to understand if you want to pass your IGCSE GCSE Maths exam. continue with your maths revision and follow the link below. Here I will explain to you what loci are and how you can construct them. I hope to see you there soon!

What are Loci

Check these links during your maths revision too and understand maths even better!!

Everything you need to pass your maths exam on one website! Follow these links during your maths revision and understand maths better. You will find all topics explained and supported by plenty of example questions. Let me know if you need more help with your maths. I will be glad to answer your questions! Good luck and have fun!