The cone and the triangle

Geometry Level 5

Not drawn to scale Not drawn to scale

In the picture, we're given an unrotated hyperbola centered at the origin. The slightly bolded box (whose vertices are intersected by the asymptotes of the graph) is defined such that the major axis is the height of the box and the minor axis is the width of the box. B B is located at a vertex of that box such that both coordinates are positive.

If the slopes of the asymptotes are 2016 and -2016, and point C C is located at a focus of the hyperbola, and A C = 1 AC = 1 , let the measure of angle A B C ABC , the purple angle, in degrees, equal δ \delta . Find 10000 δ \left \lfloor 10000 \delta \right \rfloor . Use wolfram alpha to compute the answer.


The answer is 892148.

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

1 solution

Hobart Pao
Feb 6, 2016

A B = A C AB = AC , since in a hyperbola, if c c is distance to the focus, and a a and b b are the half lengths of the axes of the hyperbola, a 2 + b 2 = c 2 a^2 + b^2 = c^2 . So then I have drawn an isosceles triangle in the photograph since c = 1 = c 2 c = 1 = c^2 . Then, the problem becomes relatively straightforward. We know that the slope of the right asymptote is 2016, and tan θ = y x or in this case, b a = 2016 \tan \theta = \dfrac{y}{x} \text{ or in this case, } \dfrac{b}{a} = 2016 , so we know that θ = arctan 2016 \theta = \arctan{2016} . Because we have an isosceles triangle, and we are asking for the an angle in the base of this triangle, use wolfram alpha to compute 10000 δ \left \lfloor 10000 * \delta \right \rfloor , where δ = 18 0 arctan 2016 2 \delta = \dfrac{180^{\circ} - \arctan{2016}^{\circ} }{2} , giving an answer of 892148 \boxed{892148} .

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...