Answer:
- 6.04 km (per angle marks)
- 5.36 km (per side hash marks)
Step-by-step explanation:
Going by the angle indicators, the ratios of corresponding sides of the similar triangles are ...
x/2000 = 4200/3500
x = 2000·6/5 = 2400 . . . . yards
Then the distance of interest is ...
(2400 yd + 4200 yd)×(0.0009144 km/yd) = 6.6×.9144 km
= 6.03504 km ≈ 6.04 km
_____
Going by the red hash marks, the ratios of corresponding sides of the similar triangles are ...
x/2000 = 3500/4200
x = 2000·(5/6) = 5000/3 . . . . yards
Then the distance of interest is ...
(5000/3 + 4200) yd × 0.0009144 km/yd ≈ 5.36 km
_____
Comment on the figure
The usual geometry here is that the outside legs (opposite the vertical angles) are parallel, meaning that the angle indicators are the correct marks. It is possible, but unusual, for the red hash marks to be correct and the angle indicators to be mismarked. The red hash marks seem tentatively drawn, so seem like they're more likely to be the incorrect marks.
