Given:
A circle with radius 7 units and chord CD = 7 units.
To find:
The measure of arc CD.
Solution:
Let O be the center of the circle.
In triangle OCD,
[tex]OC=7[/tex] (Given)
[tex]OC=OD=7[/tex] (Radii of same circle)
[tex]CD=7[/tex] (Given)
Since [tex]OC=CD=OD[/tex] all sides are equal, therefore, the triangle OCD is an equilateral triangle.
Measure of each angle of an equilateral triangle is 60 degrees. So,
[tex]m\angle COD=60^\circ[/tex]
The measure of central angle is equal to the measure of corresponding arc.
[tex]m(arcCD)=m\angle COD[/tex]
[tex]m(arcCD)=60^\circ[/tex]
Therefore, the measure of arc CD is 60 degrees.