Archaeologists attempt to reconstruct past ways of life by examining preserved bones, the ruins of buildings, and artifacts such as tools, pottery, and jewelry. During an archaeological dig, a coordinate grid is laid over the site to identify the location of artifacts as they are excavated. During a dig, three corners of a triangular building have been partially unearthed at (-1, 6), (4, 5), and (-3, -4). If each square on the grid measures one square foot, estimate the area of the floor of the building.

a. about 50ft^2

c. about 10ft^2

b. about 26ft^2

d. about 70ft^2