For large areas (lawns, gardens or fields), it may be hard to measure longer lengths, because you have no measuring device to make the long measurements (electronic device or long measuring tape or twine). In this case, an estimate can be achieved by using paces (your steps).
To estimate a length with paces, you first have to make a reasonable estimate of a regular pace while in stride. To do this, put a mark on the ground, and step back several paces. Start walking to the mark, and start counting some number of paces past the mark (e.g. 10). A that point, stop and measure the length. For example a man of six feet tall with a normal stride walked 14 paces in 40 feet. That gave him a feet per pace of 2.857 feet per pace. To compute the Feet per Pace, CLICK HERE. You can then walk off the measurements, using a steady pace, and convert the Paces to Feet by CLICKING HERE. It's a rough estimation method, but not without it's uses.
Often it is required to put land pieces together to compute to total area of land. The land shown can be accurately computed by individual triangles. The area of 5 sided land function requires the diagonals that create three triangles that are summed to compute the area in a 5 sided piece of land.