MAT 172 Law of Cosines Lab

Lab Process Steps: Please be sure to read the group member responsibilities and materials needede in the tasks tab before proceeding with the steps on this page.

1. The person with land surveyer instrument must first place the instrument approximatly 100ft from the northern end of the pond, the side closest to the road.  Please refer to the video shown below to help set up the survey instrument.   Please ensure that the instrument is  far enough away from the pond to measure a straight line from the instrument to the outer most edges of the pond as shown in the sketch above. 

2. The person with the measuring wheel will start from the surveyer instrument and measure in a straight line to the  right outer most edges of the pond and hammer in a wooden pole in the ground, record the distance.   This person will then return to the survey instrument and repeat the process measuing the distance to the left side of the pond, place the second wood pole and again record the distance.   An imaginary triangle can now be formed from the two steaks and the survey instrument, again similar to the above illustration. 

3. The person with the surveyer instrument will then look through the instrument eyepeace and locate the pole to the right of the pond.  This person will record the angle located at the top end of the instrument.   See the illustration of azimuth indicator in the below resource for details.  This file is located below the video on this page.   Without moving the legs of the instrument, this same person will swing the instrument to the other pole and again look through the eye peace of the instrument to locate the pole on the left side of the pond.  Again record the the angle located at the top of the stand.  Subtract the two angles to get the internal angle of the triangle. 

4. With the two sides and the internal angle recorded, the side opposite the angle can be calculated to get the distance across the pond using the law of cosines equation.