1.351 would round up to 1.4. You have enough decimal places in there to get your measurements into the subatomic range, +/- 10cm is accurate enough for a 1km olympic competition.
Turn to the chapter on Significant Digits in your textbook. In short, don't include more decimal places than the least precise value in the entire process.
To generally keep your accuracy realistic, NASA uses 11 decimal places to send probes to the outer planets. Pi to 39 digits will get you the circumference of the known universe to the nearest atom, and the 6 places my GPS uses gets me positioned to the nearest 50cm. So think really hard before using more digits than you can easily remember.