Please help me find the midpoint

The sixth grade art students are making a mosaic using tiles in the shape of right triangles.each tile has leg measures of 3 centimeters and 5 centimeters.i f there are 200 tiles in the mosaic what is the area of the mosaic.

Shannon drove for 540 minutes. if she traveled 65 miles per hour,how many total miles did she travel?

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?