I still nee help with this q9

Aman steps out of a plane at a height of 4,000m above the ground falls 2,000m very quickly and then opens his parachute and slowly falls the remaining 2000m to the ground what height above the ground would be the best choice for a reference point

Which conjunction is disjunction is equivalent to the given absolute value inequality? |x+2|< 18

Geometry in the diagram, ∠abc is a right angle. ∠dbc = 30°27'40". find the measure of ∠abd.