Segment AB and CD- diameter of a circle with center O. Find the perimeter of triangle AOD

Segment AB and CD- diameter of a circle with center O. Find the perimeter of triangle AOD, if chord CB = 10cm, diameter AB = 12cm

Since AB and CD are the diameters of the circle, the point O divides them in half. Then AO = ОВ = СО = ОD = AB / 2 = CD / 2.
AB = 12, then: AO = OB = CO = OD = 12/2 = 6 (cm).
The angles COB and AOD are equal, since they are vertical angles formed by the intersection of two straight lines.
Consider two triangles COB and AOD: angle COB = angle AOD, AO = OB = CO = OD = 6 cm. Triangles COB and AOD are equal on two sides and the angle between them. Then AD = CB = 10 cm.
Perimeter of triangle AOD:
P = AO + OD + AD;
P = 6 + 6 + 10 = 22 (cm).
Answer: P = 22 cm.