Answer:
Most reasonable: 16°, 20° and 22°
If Emma is very short, 25°
Step-by-step explanation:
This is trigonometry using Tangent and arc-tan
Tan=opp/adj
The length of the adjacent is 20 yards. The opposite lengths given are the bottom, 6 yards and the top, 10 yards. Assuming Emma is of average height, it seems reasonable to subtract about 1.7 to 1.9 yards, the distance of her eyes above ground level, for accuracy. But that may not be necessary, given the range of angles.
I subtracted 1.8, about 5'6"
Calculating tangent from the top:
8.2/20 = .41. arc-tan .41= 22.3°
tangent for the bottom:
4.2/20= .21 arc-tan .21 = 11.8°
If you are using a scientific calculator, once you have the ratio of the opp to adj in decimal form, use the tan- key then the decimal to convert to degrees.
