Lines CB and CA are tangents to circle O at B and A. We can conclude that, for circle O, angle BOA and angle BCA are ___, and angle BOC and angle BCO are ____.

Blank 1 options: equal, complementary, supplementary
Blank 2 options: equal, complementary, supplementary

Lines CB and CA are tangents to circle O at B and A We can conclude that for circle O angle BOA and angle BCA are and angle BOC and angle BCO are Blank 1 option class=

Respuesta :

ANSWER

Angle BOA and angle BCA are supplementary


Angle BOC and angle BCO are complementary




EXPLANATION


The two tangents from an external point to a circle, will always meet two radii of the circle at an angle of 90°.


From the diagram, the external point, is C and the two radii are OA and OB.


The sum of angles in quadrilateral OABC is 360°.


This implies that,


[tex]
< \: BOA+ \: < \: BCA+90\degree +90\degree =360\degree[/tex]


We simplify to obtain,

[tex]
< \: BOA+ \: < \: BCA =360\degree - 180 \degree[/tex]



This implies that;


[tex]
< \: BOA+ \: < \: BCA =180 \degree[/tex]



Two angles that add up to 180 degrees are called SUPPLEMENTARY angles.





Similarly the sum of interior angles of triangle BCO is 180°.




[tex]
< \: BOC+ \: < \: BCO +90\degree=180 \degree [/tex]

This implies that,


[tex]
< \: BOC+ \: < \: BCO =180 \degree \: - 90\degree[/tex]



.
[tex]
< \: BOC+ \: < \: BCO =90\degree[/tex]


Two angles that add up to 90° are COMPLEMENTARY angles.

The sum of the measure of two complementary angle is equal to the 90 degrees.  

Tt can conclude that, for circle O, angle BOA and angle BCA are __supplementary__, and angle BOC and angle BCO are __complementary__.

What is the theorem of two tangents from external point?

When the two tangent are drawn to a circle from an exterior point then according to this theorem-

  • The length of these two tangents is equal.
  • Both the tangents subtend equal angle at the center of the circle.
  • The angle between the two tangent is bisect by the line joining to the exterior point and the center.

Given formation-

The center of the circle is O.

Lines CB and CA are tangents to circle O at B and A.

In the given properties of theorem of two tangents from external point is shown in the attached image below.

In the given image,

[tex]m\angle A=m\angle B=90^o[/tex]

In the quadrilateral OACB the measure of the angle is equal to the 360 degrees. Thus,

[tex]m\angle A+m\angle B+m\angle O+m\angle C=360^o\\90+90+m\angle O+m\angle C=360^o\\m\angle O+m\angle C=180^o[/tex]

As the sum of the measure of two supplementary angle is equal to the 180 degrees. Thus angle BOA and angle BCA are supplementary angles.

In the [tex]\Delta OBC[/tex] the angle OBC is equal to the 90 degrees and the sum of all the angles is equal to the 180 degrees for the triangle. Thus,

[tex]\angle BOC+\angle OBC+\angle BCO=180^o\\90+\angle OBC+\angle BCO=180^o\\\angle OBC+\angle BCO=90^o[/tex]

As the sum of the measure of two complementary angle is equal to the 90 degrees. Thus angle BOC and angle BCO are complementary angles.

Thus it can conclude that, for circle O, angle BOA and angle BCA are __supplementary__, and angle BOC and angle BCO are __complementary__.

Learn more about the theorem of two tangents from external point here;

https://brainly.com/question/8705027

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