JEE MainMathematicsStraight Lines and Pair of Straight LinesMCQ+4 / −1
If a ABC has vertices A(–1, 7), B(–7, 1) and C(5, –5), then its orthocentre has coordinates :
- A(–3, 3)
- B(3, –3)
- C
- D
View written solutionFree
Correct answer: A
- Given vertices
We need the orthocentre, i.e. the point of intersection of the altitudes.
- Find slope of side
Points and give
So the altitude from is perpendicular to , hence its slope is
Equation of altitude through :
- Find slope of side
Points and give
So the altitude from is perpendicular to , hence its slope is
Equation of altitude through :
or
- Find intersection of the two altitudes
Solve
Equating,
Multiply by :
Then
So the orthocentre is
- Check with options
Option A: ✅
Hence the correct answer is A.
- Comparison with stored answer
Stored correct answer: A
Our derived answer: A
They match.
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