Who has discord and can help me

Landon is entering the science fair. he has a budget of $115. he has spent 20 percent of the money on new materials. how much does landon have left to spend?

The measure of angle 0 is 600 degrees

Asource of laser light sends rays ab and ac toward two opposite walls of a hall. the light rays strike the walls at points b and c, as shown below: what is the distance between the walls?