On https://www.arduino.cc/en/Tutorial/BuiltInExamples/tonePitchFollower

Text says: "Connect one terminal of your speaker to digital pin 9"
Schematic shows speaker connected to digital pin 8
Software: tone(9, thisPitch, 10);

Text says:
"Hardware Required...100 ohm resistor"
"Connect one terminal of your speaker to digital pin 9 through a 100 ohm resistor"
Schematic shows speaker connected through 10K ohm resistor

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When I completed this project, I connected the speaker through a 220 ohm resistor.
100 ohm resistor + 8 ohm speaker = 46.3 mA
220 ohm resistor + 8 ohm speaker = 21.93 mA