An arch is in the form of a parabola with its axis vertical. The arc is 10m high and 5m wide at the base. How wide is it 2m from the vertex of the parabola?

Options

A. `sqrt(2)`
B. `sqrt(3)`
C. `sqrt(5)`
D. 4

Answer

C

Explanation

The origin of the coordinate plane is taken at the vertex of the arch in such a way that its vertical axis is along the positive y-axis.


The equation of the parabola is of the form `x^2=4ay` (as it is opening upwards)


Since, the parabola passes through point `(5/2,10)`

`(5/2)^2=4a(10)`

`impliesa= 4xx4xx25/10= 5/32`

So, the equation of arch of parabola is

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