Answer
21 pedal strokes
Work Step by Step
First convert 357 inches to feet
$357 in = 29.75 ft$
Set up a proportion to find $x$ pedal strokes
$\frac{6}{29.75}=\frac{y}{100}$
Write the cross products
$6(100)=29.75y$
Simplify
$600=29.75y$
Divide both sides by 29.75
$\frac{600}{29.75}=\frac{29.75y}{29.75}$
Simplify
$20.168=y$
About $21$ pedal strokes