A telephone chord has 8 circular spirals, each spiral having a diameter of 12a+6b. find the total length of chord?

The perimeter of one spiral: D*π, D=12a+6b⇒

(12a+6b) * π=6*π (2a+b) = 18.85 (2a+b)

A telephone chord has 8 circular spirals so total length of chord is:

8*18.85 (2a+b) = 146 (2a+b) = 292a+146b

The total length of telephone chord is 292a+146b.