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## Homework Statement

A dentist's chair of mass 207kg is supported by a hydraulic lift having a large piston of cross-sectional area 1403.0cm^2. The dentist has a foot pedal attached to a small piston of cross-sectional area 78.0cm^2. What force must be applied to the small piston to raise the chair.

## Homework Equations

P=F/A

Fp/Ap = Fc/Ac

## The Attempt at a Solution

Fp = Fc/Ac * Ap

Fp = 207kg/1403 * 78 = 112.78

Okay so I have already gotten the answer 112.78N but I don't understand a few things about this question...

- Why does Fp/Ap = Fc/Ac??

- Why is 207kg relate to 1403cm^2?

- What is the subscripts p and c???