Maths problem involving Coordimate Geometry

[Sanosuke Sagara]

find the equation of a straight line whose x-intercept and y-intercept are a and b respectively.If this line varies such that $$\frac{1}{a^2}$$ + $$\frac{1}{b^2}$$ = $$\frac{1}{c^2}$$with c as a constant,show that the locus of the foot of the perpendicular from the origin to this line is the curve
$$X^2$$ +$$Y^2$$ = $$C^2$$.


I want to ask what is meant by the phrase 'foot of the perpendicular from the origin to this line ' ?

I hope that somebody will help me to explain the meaning and thanks for anybody that spend some time on this question.

 

[Data]

The 'foot of the perpendicular from the origin to this line' means the curve which the intesection of the line and the perpendicular forms as $$a$$ and $$b$$ are varied. This intersection point changes with $$a$$ and $$b$$, and the path that it traces they move through all their possible values is what the question is looking for.