A, B, R and P are four points on a circle with centre O - Edexcel - GCSE Maths - Question 1 - 2018 - Paper 3
Question 1
A, B, R and P are four points on a circle with centre O.
A, O, R and C are four points on a different circle.
The two circles intersect at the points A and R.
CPA, C... show full transcript
Worked Solution & Example Answer:A, B, R and P are four points on a circle with centre O - Edexcel - GCSE Maths - Question 1 - 2018 - Paper 3
Step 1
Prove that angle CAB = 180 - angle OAR
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Using the fact that angles subtended by the same chord at the circumference of a circle are equal, we can write:
∠CAB+∠OAR=180∘
This is because CAB and OAR subtend the same arc AB.
Step 2
Establish relationship using angle on a straight line
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Since A, O, R are collinear, we have:
∠OAR+∠CRB=180∘
This implies that:
∠CAB=180∘−∠CRB.
Step 3
Use the properties of circles
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The angles subtended by the same arc are equal, which tells us:
∠ABC=∠CRB.
Step 4
Complete proof and conclusion
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
From the previous relationships, we have:
∠CAB=180∘−∠CRB and \angle ABC = \angle CRB.$$ Therefore,