OD = OB OC = OC
∠ ABC = 90 = ∠ CDO (the line between the tangent point of a straight line and a circle and the center of the circle is perpendicular to the straight line)
∴RT△ODC≌RT△OBC
BC =BD
(2)
∵RT△ODC≌RT△OBC
∴CD=CB
∴∠CDB=∠CBD
∠∠CDO = 90°
∴∠ADE+∠CDB=90
∠ABC = 90°。
∴∠ABD+∠CBD=90
∴∠ADE=∠ABD
(3)
∫AD is tangent to the circle at point d.
∴AD square = =AE×AB
∴2*2= 1*AB
AB=4
EB=3
The diameter of this circle is 3.
A. What are the majors of Zhejiang Gongshang University?
Zhejiang Gongshang University was upgraded to touris