If the tangents at the points P and Q on the circle meet at the point , then the area of triangle PQR is:
- A
- B
- C
- D
If the tangents at the points P and Q on the circle meet at the point , then the area of triangle PQR is:
Correct answer:C
Standard Method
Given: The circle is and the tangents at points P and Q meet at .
Find: The area of triangle PQR.
The equation of the circle is:
The equation of the line joining the points and is derived using the coordinates of the points. We find the equation of the line to be:
Using the distance formula, the area of triangle is given by:
After calculating the distances, we find:
Therefore, the area of triangle PQR is , so the correct option is C.
Extracted Explanation
Given: The tangents from touch the circle at and .
Find: The area of triangle .
From the extracted solution, the chord of contact is taken as:
Then the area is evaluated using the distance-based relation mentioned in the solution:
The final computed value given in the solution is:
Hence, the correct answer is .
Using the centre-radius form incorrectly. First rewrite the circle carefully before applying tangent or chord-of-contact results; sign errors in the linear terms change the geometry.
Confusing the chord of contact with a tangent line. joins the points of contact, so its equation is not the same as either tangent at or .
Using an incorrect area formula for triangle . After finding the base , use the perpendicular distance from to the line ; do not use distances from the centre unless justified.
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