NCERT Class 11 Engineering Graphics Chapter 2 Book PDF 2026-27

The NCERT Book PDF for Class 11 Engineering Graphics Chapter 2 Lines, Angles, and Rectilinear Figures gives students the exact drawing rules, line types, lettering basics, dimensioning method, and plane-geometry constructions used in the 2026-27 CBSE course.

• Page count: 71 pages of textbook content for the drawing basics unit.
• Core focus: line conventions, angles, lettering, dimensioning, triangles, quadrilaterals and polygons.
• Best use: read the PDF once, then practise each construction on a drawing sheet.

This Engineering Graphics PDF is kept as the textbook chapter students need for the 2026-27 syllabus, with the main drawing checks explained in plain language by Collegedunia.

What the Lines, Angles, and Rectilinear Figures PDF Contains

The chapter starts with the role of Engineering Graphics as a technical language. It then moves into line quality, drawing instruments, lettering, dimensioning, and simple rectilinear constructions. Students should treat this PDF as a drawing-practice chapter, not a reading-only chapter.

Lines and Angles Drawing Basics for Class 11

Source: VISHWAKARMA ENGINEERING DRAWING CLASSES on YouTube

Engineering Graphics Line Types Every Student Must Know

Line type is the first scoring check in this chapter. The same object can look correct in shape but still lose marks if the visible outline, hidden edge or dimension line is drawn with the wrong thickness.

• Continuous thick line: visible outlines and sheet boundary lines.
• Thin continuous line: construction, projection, extension and dimension lines.
• Chain thin line: centre lines and axes of circles or symmetrical objects.
• Short dashed line: hidden outlines that cannot be seen from the viewing side.

Rectilinear Figure Construction Flow for Drawing Sheets

Rectilinear figures are shapes made only with straight lines. In this chapter, that means triangles, squares, rhombuses, trapeziums, pentagons, hexagons and octagons. Most mistakes happen because students start drawing before listing the given data.

1. Write the given sides, angles, diagonals, perimeter or special condition.
2. Draw the base line with the correct scale and line weight.
3. Construct the angle or parallel line with compass and set-square.
4. Join the final vertices with continuous thick object lines.
5. Add dimensions with thin lines and arrowheads, then check the final figure.

Common Mistakes Students Make in Lines and Dimensioning

This unit looks easy because every figure uses straight lines. The marks are lost in small presentation details. Fix these before moving to orthographic projection or isometric drawing.

• Using one line weight everywhere: keep visible outlines thicker than dimension lines.
• Writing dimensions inside the figure: place dimension text clearly near the dimension line.
• Skipping construction lines: keep light construction lines until the final shape is complete.
• Ignoring lettering proportion: use standard height and spacing for letters and numerals.

Student Feedback on the Engineering Graphics Drawing Basics Unit

How to Use the Lines, Angles, and Rectilinear Figures PDF

Do not read this chapter like a theory note. Keep a pencil, scale, compass and set-square ready. Read one sub-topic, then redraw the example on plain paper before moving ahead.

• First pass: learn the names and purpose of each line type.
• Second pass: practise lettering, numerals and dimension placement.
• Third pass: draw triangles and polygons with the given measurements.
• Final check: compare line weight, arrowheads and labels with the textbook figure.

Engineering Graphics Chapter 2 Related Resources

All Chapters of Engineering Graphics with NCERT Book PDFs