Anyone good with geometry need to solve for c

Use set builder notation to represent the following set: { -3, -2, -1, 0}

Type the correct answer in the box. use numerals instead of words. if necessary, use / for the fraction bar.a city water tank holds 20 gallons of water. a technician empties 25% of the tank. how many more gallons of water must be removed from thetank so that it has 5 of the water that it started with: the technician must removemore gallons of water for the tank to have 5 of the water that it started with.

In triangle abc, angle c is a right angle. find the value of the trig function indicated. find tan a if c = 17 and a = 8