A ladder 39 ft long leans against a vertical wall. If the lower end is being moved away from the wall at the rate of 4 ft/sec, how fast is the height of the top changing (this will be a negative rate) when the lower end is 15 feet from the wall?

Aman is 6 feet 3 inches tall. the top of his shadow touches a fire hydrant that is 13 feet 6 inches away. what is the angle of elevation from the base of the fire hydrant to the top of the man's head?

How do i start to solve? would appreciate a walk-thru! a bird sitting 16ft above the ground in an apple tree dislodges an apple. after how many seconds does the apple land on the ground? (assuming that no branches will interfere with it's fall)

Olga bought a new skirt that cost $20. sales tax is 5%. how much did olga pay, including sales tax? 7.