As shown in the figure, it is known that AB is the diameter of ⊙ o, Pb is the tangent of ⊙ o, B is the tangent point, Op ⊥ chord BC is at point D and intersects ⊙ o at point E. (1) prove: ∠ OPB = ∠ AEC; (2) if point C is the triad point of semicircle and ACB, please judge which special quadrilateral AOEC is? And explain the reason
(1) It is proved that: ∵ AB is the diameter of ⊙ o, Pb is the tangent of ⊙ o, ∵ Pb ⊥ ab. ∵ OPB + ∠ POB = 90 °. ∵ op ⊥ BC, ∵ ABC + ∠ POB = 90 °. ∵ ABC = ∠ OPB. Also ∵ AEC = ∠ ABC, ∵ OPB = ∠ AEC. (2) the quadrilateral AOEC is rhombic
As shown in the figure, AB is the diameter of circle O, BD and PD tangent circle O at points B and C, P, a and B are collinear, and prove that Po × Pb = PC × PD
Certification:
∵ BD and PD are tangent lines of circle o
∴∠PCO=∠PBD=90º
And ∵ ∠ OPC = ∠ DPB [common angle]
∴⊿OPC∽⊿DPB(AA’)
∴PO/PD=PC/PB
∴PO×PB=PC×PD
PA.PB Tangent circle O to two points a and B, tangent through P, is called circle to C. D, parallel to CD through B, connect AE and PD to m, and prove that M is the midpoint of DC
Urgent solution! Thank you very much!
Let's do it! AB intersects CD with n ﹥ PAB = ﹥ BAE = ﹥ PMA, so ⊿ pan is similar to ⊿ PMA, so PC * PD = PA * PA = PN * PM. It is proved that P, C, N.D harmonic point sequence (PC / CN = Pd / DN) PC / PD = (PC / DN) * (dN / CN) = (AC / AD) * (CB / BD) (left and right triangles are similar) = (AC * CB * sin ﹥ ACB) / (ad * BD * sin