20 A, B, C and D are points on the circumference of a circle, centre O - Edexcel - GCSE Maths - Question 20 - 2022 - Paper 2
Question 20
20 A, B, C and D are points on the circumference of a circle, centre O.
ADE and BCE are straight lines.
Work out the size of angle CDE.
Give a reason for each stage... show full transcript
Worked Solution & Example Answer:20 A, B, C and D are points on the circumference of a circle, centre O - Edexcel - GCSE Maths - Question 20 - 2022 - Paper 2
Step 1
Find angle AOD
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Answer
We know that angle AOD is created by lines AO and OD. Since angle ADB is an exterior angle to triangle ACB, it can be calculated as follows:
AOD=360exto−132exto−16exto=212exto
Step 2
Find angle BOD
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Answer
Using the property that angles at the centre are double the angles at the circumference, we can determine angle BOD: