Find the area of the triangle formed by the lines joining the vertex of the parabola x2 = 12y to the ends of its latus - rectum.
Given that we need to find the area of the triangle formed by the lines joining the vertex of the parabola x2 = 12y to the ends of its latus - rectum.
Comparing it with the standard form of parabola x2 = 4by.
⇒ Vertex is 0(0, 0)
⇒ Ends of latus rectum is (2b, b), (- 2b, b)
⇒ 4b = 12
⇒ b = 3
⇒ Ends of latus rectum is (2(3), 3), (- 2(3), 3)
⇒ Ends of latus rectum is A(6, 3), B(- 6, 3)
We know that area of the triangle with the vertices (x1, y1), (x2, y2) and (x3, y3) is
⇒
⇒
⇒
⇒
⇒
⇒ A = 18sq.units.
∴The area of the triangle is 18 sq.units.