The chord ab is 26 cm oa and ob is the radius of the circle and the angle aob is 120 degrees.
The chord ab is 26 cm oa and ob is the radius of the circle and the angle aob is 120 degrees. Find the distance from the point o to the chord ab.
From point O, the center of the circle, draw the radii OA and OB. Then the formed triangle AOB is isosceles, OA = OB. From point O we draw the height OH to the chord AB, which will also be the bisector and median of the triangle AOB.
Then AH = BH = AB / 2 = 26/2 = 13 cm.
Angle AON = AOB / 2 = 120/2 = 600.
In the right-angled triangle AOН, we determine the length of the OH leg.
The tangent of the angle of a right-angled triangle is equal to the ratio of the opposite leg to the adjacent one.
tgAOH = AO / OH.
OH = AН / tgAOH = 13 / √3 = 13 * √3 / 3 cm.
Answer: The distance from point O to the chord is 13 * √3 / 3 cm.