A and B are points on a circle, centre O - Edexcel - GCSE Maths - Question 11 - 2018 - Paper 1
Question 11
A and B are points on a circle, centre O.
BC is a tangent to the circle.
AOC is a straight line.
Angle ABO = x°.
Find the size of angle ACB, in terms of x.
Give yo... show full transcript
Worked Solution & Example Answer:A and B are points on a circle, centre O - Edexcel - GCSE Maths - Question 11 - 2018 - Paper 1
Step 1
Identify the Relationship Between Angles
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Answer
Since BC is a tangent to the circle at point B, angle ABO (which is equal to x°) forms a right angle with line BC. Therefore, angle ABC is equal to 90°.
Step 2
Use the Angles in a Triangle
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Answer
In triangle ACB, the sum of the interior angles is 180°. We have:
extAngleACB+extAngleABC+extAngleCAB=180°
Substituting the known values:
extAngleACB+90°+(180°−x°)=180°
Step 3
Simplify the Equation
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Answer
Now, simplify the equation:
extAngleACB+90°+180°−x°=180°
So, we can rearrange it to find angle ACB:
extAngleACB=x°−90°+90°=90°−x°
Step 4
Final Answer
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