Hi i need help on these question can some take out the time to explain them briefly

Safety guidelines specify that a ladder should form an angle between 70° and 80° with the ground. If a ladder is 4 m long, determine the range of distances from the wall that the foot of the ladder may be placed to fall within the safety guidelines?

A staircase is being constructed in a new house as displayed on the right. Each tread is 18 cm and each riser is 10 cm. Determine the angle of inclination of the stairs.

A tunnel must be constructed through a mountain. The angle of elevation from one side of the mountain is 38.2°. The angle of elevation from the other side of the mountain is 27.4°. The height of the mountain is 575 m. What is the length of the tunnel through this mountain?

Thanks in advance Please