Please help me using product rule

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

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

  cassidy wants to cut the yellow fabric into strips that are 0.3 yards wide. how many strips of yellow fabric can cassidy make? yellow fabric 16 yards for $108.00.