Answer:
x= 21
y= 3
z= 21
Explanation:
Let the center be O,
=> Triangle AOD is an Isosceles triangle so AO≅DO, "21 = x"
=> Line AC is divided in two equal parts by the center so if AO= 21 then
7y = 21, and thus "y = 3"
=> BOC is also an Isosceles triangle so CO ≅ BO, if CO = 21 (7y → 7*3) then so will be BO. Therefore "z = 21"