Hi,

So I have a problem that reads as follows:

[PQ] is a chord of a circle. R lies on the major arc of the circle. Tangents are drawn through P and through Q. From R, perpendiculars [PA], [PB] and [PC] are drawn to the tangent at A, the tangent at B and [AB] respectively. Prove that RA.RB = RC^2.

It's not that I don't get similarity, it's rather the phrasing of the problem...how can you have perpendiculars PA, PB and PC from R???