locate a missing point on the ground: a. You need at least three reference points b. You need at least one reference points c. You need at least four reference points d. You need at last two reference points

i need the answer quickly

A surveyor is surveying a piece of land records the following information. The land is a triangular shape. The surveyor measures with a total station the line from a to b is 2.3 km, and the line from c to a is 6.2 km. The measures angle between lines a-b and c-a is 72 degrees. Compute the length from b to c on the land and calculate the total length of the perimeter of the land

a)      The following data is given.                     i.            Higher contour is 100.830                    ii.            Lower contour is 100.580                  iii.            Distance from higher contour to grid is 24 mm Distance between contours is 34 mm