In Rt△OAD, cos∠BAO=ADOA= 13.

∴AD= 13AO= 1，

∴BD=AD= 1，

∴AB=2AD=2.

(2) connect OB, PA, PC,

⊙P and⊙ o are tangent to point a,

Points p, a and o are on a straight line.

PC = PA，OA=OB，

∴∠PCA=∠PAC=∠OAB=∠OBA，

∴PC∥OB.

∴ACAB=PAAO，

∴AC=PA？ ABAC=2x3，

∫OD2 = OA2-AD2 = 32- 12 = 8，CD=AD+AC=23x+ 1，

∴OC=OD2+CD2=(23x+ 1)2+8，

∴ y =134x2+12x+81,(the domain is x > 0).

(3) When ≥P and ≥O are circumscribed,

∠∠BOA =∠OCA，∠CAO=∠POC，

∴△OAC∽△OCP.

∴OAOC=OCOP，

∴OC2=OA？ OP，

∴ 19(4x2+ 12x+8 1)=3(3+x)，

∴x 1=0 (not in conformity with the meaning of the question, omitted), x2= 154,

At this time, the radius of p is 154,

When ≥P and ≥O are inscribed,

I've praised it all. I've stepped on it. What is your evaluation of this answer? Put away comments//high quality or satisfaction or special types or recommended answers dottimewindow.iperformance & window.iperformance.mark ('c _ best',+newdate); Lawyer recommendation service: If your problem is not solved, please describe your problem in detail and provide free professional consultation through Baidu Legal Pro. Other similar problems 2016-12-01(2013? As shown in the figure, m, n and p are three points on a semi-circular arc with a diameter of MN, and point O is the center of the semi-circular arc. ∠ MOP = 60.52016-07-12 (2014? As shown in the figure, it is known that the radius of ⊙O is 1, the acute angle △ABC is inscribed in ⊙O, BD⊥AC is at point, and OM⊥AB is at point M, if OM =12,2016-65438. As shown in the figure, CD is the diameter of ⊙ O, and A and B are two points on ⊙ O. If ∠ B = 20, the number of ∠ADC is _ _ _ _ 2016-05-28 (2009? As shown in the figure, two circles with equal radii ⊙O 1 and ⊙O2 intersect at p and q, with the center O 1 on ⊙O2, and the tangent of PT is ⊙O 1 P2014-6544. Suzhou simulation) as shown in the figure, the radius ⊙O is 4cm, the straight lines L and ⊙O intersect at points A and B, AB=43cm, and P is the moving point on the straight line L,1cm12016-07-30 (20/kloc). As shown in the figure, and the tangent AM of ⊙O is C 20 16-05-24 (2065438+), a model of Chongming County is known: as shown in the figure, at △ABC, ∠ ACB = 90, AC=CB, CD⊥AB is at point D, ∠. As shown in the figure, A is a point above ⊙O, and the radius OC is equal to 2. If ∠ ACD = 45, then the length of the chord AD is _ _ _ _ More similar questions? & gt recommended for you: F.context('cmsRight', [{'URL':'/d01373f082025aaf511aa256e9edab64034f1a07? x-BCE-process = image % 2f resize % 2Cm _ lfit % 2Cw _ 450% 2Ch _ 600% 2c limit _ 1% 2f quality % 2Cq _ 85% 2f format % 2Cf _ auto '，' contractId':'A24KA00562 '，}，{ ' URL ':/s？ word = % E6 % AC % A7 % E6 % B4 % B2 % E6 % 9D % AF & sa = searchpromo _ ozb _ zhidao _ tuijian '，' src ':'/3 BF 33 a 87 e 950352 AAF 5 df 4954 143 fbf2b 2 1 18 b6b？ x-BCE-process = image % 2f resize % 2Cm _ lfit % 2Cw _ 450% 2Ch _ 600% 2c limit _ 1% 2f quality % 2Cq _ 85% 2f format % 2Cf _ auto '，' contractId ':' '，}])； The price of electric cars has dropped many times. Is the quality guaranteed? What impact will the "network toilet" have? Is Huaqiang North's second-hand mobile phone reliable? Why is the cost of cancer treatment getting higher and higher? I recommend f.context ('recbrand', [{"img": "\/86D6277F9E2F07083523F69DFB 24B 899A901F20d? x-BCE-process = image % 2f resize % 2Cm _ lfit % 2Cw _ 450% 2Ch _ 600% 2c limit _ 1% 2f quality % 2Cq _ 85% 2f format % 2Cf _ auto "，" url":"/hm.js？ 6859 ce 5a af 00 FB 00387 e 6434 E4 FCC 925 "； var s = document . getelementsbytagname(" script ")[0]； s.parentNode.insertBefore(hm，s)； })(); window . TT = 1720065987；