JEE Main 2022 · 28 Jul · Shift 2 · Mathematics Q73

MathematicsSingle correct+4 / -1Question 73 of 90

Let the tangents at two points A and B on the circle $x^2+y^2-4x+3=0$ meet at origin O (0, 0). Then the area of the triangle OAB is :

\dfrac{3\sqrt3}2

\dfrac{3\sqrt3}4

\dfrac3{2\sqrt3}

\dfrac3{4\sqrt3}

Answer and worked solution

Official answer: B

Circle centre (2, 0), radius 1; O is 2 away, tangent length $\sqrt3$ .

Triangle. Distance from O to AB is $\frac32$ and half of AB is $\frac{\sqrt3}2$ , so the area is $\frac{3\sqrt3}4$ .

(B)

Topics:Tangents and normals Chord of contact

JEE Main 2022 · 28 Jul · Shift 2, Mathematics question 73