Is the degree of the chord tangent angle equal to half the degree of the clamped arc?

That is, equal to the circumferential angle of the clamped circular arc pair? Available ∠APQ=∠ARP and ∠A=∠A = ∠ a = ∠ a.

You can get △APQ∽△ARP, and you can get PA2=AQ*AR, that is, xy=36, xy36?

(2) Links or works, OQ

Prove △APC∽△AOP?

Available PA2=AE*AO= AQ*AR.

Re-certification △AQC∽△ARO?

Get ∠ACQ=∠ARO=∠BCD.

By ∠ROQ=2∠D and 2∠ORQ+∠ROQ= 180? Get BCD+D = 90? RD is perpendicular to the straight line OA