Final answer:
The angle of elevation cannot be determined based on the given information.
Step-by-step explanation:
To find the angle of elevation from Mary to Rhian, we can create a right triangle with Mary, Rhian, and the base of the building. The distance from Mary to the base of the building is the adjacent side of the triangle, and the height of the building is the opposite side. Using the tangent function, we can solve for the angle of elevation.
Tangent(theta) = opposite/adjacent
Tan(theta) = height/4.3
Theta = arctan(height/4.3)
Since we don't have the height of the building, we cannot determine the angle of elevation. Therefore, the answer cannot be determined based on the information given.