Case Study 1: Parallel and Diagonal Lines An engineer needs to draft parallel walls and $30^\circ$ lines. Identify the instruments.

Case Study 2: Curves and Scaling Identify instruments for drawing non-circular curves and measuring scaled distances.

Case Study 1: Hidden and Center Lines A circular hole is drilled in a block. What lines represent its boundaries and center in a front view?

Case Study 2: Phantom and Dimension Lines Identify lines used for alternating positions of a moving part and for specifying sizes.

Case Study 1: Standard Violations A draftsperson mixes uppercase and lowercase, and uses varying letter heights.

Case Study 2: Slant and Proportions A draftsperson randomly slants letters left and right.

Case Study 1: Border Placement A drawing is placed on an A3 sheet with borders on the exact physical edge.

Case Study 2: Revision Blocks A revision is made without updating the revision block.

Basic Example: Bisecting a Line Describe how to bisect a line segment AB of length $50\text{ mm}$.

Intermediate Example: Bisecting an Angle Describe how to bisect angle AOB.

Advanced Example: Inscribed Hexagon Construct a regular hexagon inside a circle of radius $R = 25\text{ mm}$.