Year 11
Core

Circle Theorems: Angles in a cyclic quadrilateral

Year 11
Core

Circle Theorems: Angles in a cyclic quadrilateral

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Lesson details

Key learning points

  1. In this lesson, we will learn that opposite angles in a cyclic quadrilateral sum to 180 degrees. We will prove this result with a general case.

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3 Questions

Q1.
Work out the size of angle x.
An image in a quiz
104º
128º
38º
Correct answer: 52º
Q2.
Work out the size of angle y.
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147º
Correct answer: 33º
57º
66º
Q3.
Work out the size of angle x.
An image in a quiz
21.5º
Correct answer: 43º
86º
90º

3 Questions

Q1.
What can you say about the angles x and y in this diagram?
An image in a quiz
They are both acute angles.
They are both obtuse angles.
Correct answer: They will add together to equal 180º.
They will add together to equal 90º.
Q2.
Work out the size of angle x.
An image in a quiz
110º
Correct answer: 115º
185º
70º
Q3.
Work out the size of angle y.
An image in a quiz
Correct answer: 106º
109º
149º
74º