Geometric Diagrams (3) and (4): Rectangle Division and Diagonal Line Representation #3809574 (License: Personal Use)

Diagram (3) is a horizontal rectangle divided vertically, with the left half filled with dense vertical lines indicating shading or material density, while the right half remains blank. Diagram (4) is a diagonal line segment oriented from lower-left to upper-right, featuring a thick black base that tapers to a fine point, possibly representing a ray, needle, or vector with magnitude variation.

This image appears in technical or educational contexts such as physics textbooks, optical instrument manuals, or geometry problem sets-often illustrating concepts like light rays, cross-sections, or proportional scaling. User intent likely involves understanding schematic notation or interpreting labeled diagrams in STEM learning.