An equilateral triangle is inscribed in the parabola , where one vertex is at the vertex of the parabola. Find (a) the length of the side of the triangle, (b) area of triangle ABC.
A parabolic reflection with diameter PR = 20 cm and OQ = 5 cm is shown below:
Here, vertex of the parabola is (0, 0)
Let the focus be S (a, 0)
Let the equation of the parabola be
Now, PR = 20 cm PQ = 10 cm
Also, OQ = 5 cm
∴ Point P is (5, 10)
Since it lies on the parabola
∴
∴ Focus is S (5, 0) which is same as point Q.