Respuesta :
A quadrilateral has a sum of interior angles equal to 360.
Angle A & C are each 90 degrees, and we're given that AOC (arc AC) is 160 degrees.
Therefore
angle ABC=360-160-90-90=20 degrees
Angle A & C are each 90 degrees, and we're given that AOC (arc AC) is 160 degrees.
Therefore
angle ABC=360-160-90-90=20 degrees
Answer:
m∠ABC=20°
Step-by-step explanation:
Consider quadrilateral ABCO. The sum of the measures of all interior angles in quadrilateral ABCO is equal to 360°.
Lines BA and BC are tangent to the circle, then the radii OC and OA are perpendicular to the tangent lines BC and BA. Therefore,
- m∠BCO=90°;
- m∠BAO=90°.
The measure of the angle AOC is 160° (because the measure of arc AC is 160°). So,
m∠ABC+m∠BCO+m∠BAO+m∠AOC=360°,
m∠ABC=360°-(m∠BCO+m∠BAO+m∠AOC)=360°-(90°+90°+160°)=20°.