Help please with this problem!

What two criteria are needed for triangles to be similar

Scale factor of 2 is used to enlarge a figure as shown below the area of is 18 in.²

Nick has box brads. he uses 4 brads for the first project. nick let’s b represent the original number of brads and finds that for the second project, the number of brads he uses is 8 more than half the difference of b and 4. write an expression to represent the number of brads he uses for the second project.