Plane geometry -- Circles

My solutions will not involve the reasons. I hope you can remember all of them and know how to use them. Here, I would like to focus on the steps to do questions about circle.

Step 1: Underline all the clues from the questions

Step 2: Label the required angle as x

Step 3: Use the clues one by one and you will get the answer.

If you have some clues unused, you better check again to see any mistakes are made.

Answer : C

Clues: tangent, arc BC = arc AC

Answer : B

Origin should be center. 

This is a difficult question. Try to remember the method used. Also, recall the different methods of calculating the area of a triangle.

Answer : D

This kind of questions has appeared in DSE. The method is simple and please try your best to remember it.

Clue 1: tangents
Clue 2: 90 degree

Thus, you should be aware that theorem about tangent and 90 degree must be used.

Answer : E

Origin should be center. 

Learn how to add the lines and help you finish the question. It is a common question.

pi/6 = 30 degree




Answer : E

We only know how to find area of sectors and triangle. So we try to divide the figure into sectors and triangle only by drawing OC.

A similar question appears in DSE. Just recall the area you have learnt to compute.