All triangles have the same value, and all circles have the same value. What is the sum of three circles?
+1694 Δ = x O = y
3x + 2y = 21
x = (21 - 2y) / 3
3y + 2x = 19
3y + 2(21 - 2y) / 3
y = 3 x = 5
3y = 9
+1694 Oops...
corrections:
Δ = x O = y
3x + 2y = 21
x = (21 - 2y) / 3
3y + 2x = 19
3y + 2(21 - 2y) / 3 = 19 
y = 3 x = 5
3y = 9
