In an ideal classroom cylinder, cap-side gauge pressure is 550 kPa and the other side is at atmosphere. Piston diameter is 80 mm; rod diameter is 26 mm. Use π=3.1416. Force=gauge pressure in Pa×effective area in m². For a separate retraction calculation apply the same gauge pressure to the rod side and vent the cap side. Ignore friction; this is not brake-service guidance.
Calculate the effective rod-side area in m². Keep intermediate values unrounded; round the final result to four decimal places if necessary.