A pilot flying at an altitude of 1.8 km sights the runway directly in front of her. The angle of depression to the beginning of the runway i

I think you must mean 31°  and 23°

The length of the runway is given by

1.8km*[tan(90-23) - tan(90-31)] =

1.8km* [ tan(67) - tan(59)] = about 1.24 km

Here's a pic of the situation........

I think the "31mc006-1.jpg." isn't necessarily a common unit of angle measure in trig........!!!!!

Re-post ????