A bricklayer is building a wall. Each layer of the wall has the same number of bricks.
The points on the following coordinate plane show how many bricks he used to make 2, 3, and 4 layers of the wall. How many bricks are used in 1 layer of the wall?

Look at the figure below: triangle abc is a right triangle with angle abc equal to 90 degrees. the length of ac is 5 units and the length of ab is 4 units. d is a point above c. triangle adc is a right triangle with angle dac equal to 90 degrees and dc parallel to ab. what is the length, in units, of segment cd?