∠C=∠D=90

BP = 3PC

That is BP/PC=3

BC=BP+PC

∴PC/BC= 1/4

Let PC=k then AD=BC=DC=4k.

Q is the midpoint of CD.

∴DQ=QC= 1/2DC=2k

∴DQ/PC=2/ 1

AD/QC=2/ 1

∴ DQ/PC=AD/QC

At △ADQ and △QCP,

DQ/ PC = Advertising/Quality Control

∠C=∠D

∴△ADQ∽△QCP

(2) Similarity.

∫△ADQ∽△QCP

∴AQ/QP=AD/QC

Also: DQ = royal counsel

∴AQ/QP=AD/DQ

That's AQ/QP/DQ.

(Ratio substitution, Pythagorean theorem calculates AQ and QP [k], and the ratio is equal, so it is similar. )