Not exactly the same but for dryers the rule of thumb is that a 90 degree bend adds 5’ to the effective length.
Here is Mechanical Code info for reference:
Dryer Exhaust Duct Fitting Type Equivalent Length
4” radius mitered 45 degree elbow 2 feet 6 inches
4” radius mitered 90 degree elbow 5 feet
6” radius smooth 45 degree elbow 1 foot
6” radius smooth 90 degree elbow 1 foot 9 inches
8” radius smooth 45 degree elbow 1 foot
8” radius smooth 90 degree elbow 1 foot 7 inches
10” radius smooth 45 degree elbow 9 inches
10” radius smooth 90 degree elbow 1 foot 6 inches
The radii listed are the radius of the bend.
These are all for 4" round metal exhaust duct (not flexi-duct).
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