C075 · Euclid & PolygonsISO 128 · 1:1
Octagon with Square Cutout — composite figure at 1:1 scale with dimensions, area 39.2 cm²
A = 2(1+√2)·l² − l² = (1+2√2)·l²

High school (grades 9–10) · TypeLab 2D

Octagon with Square Cutout

Octagon with Square Cutout: a composite plane figure made of a regular octagon with side 3.2 cm, minus a square with side 3.2 cm. It is a classic high school (grades 9–10) geometry problem (“Euclid & Polygons”). The net area is 39.2 cm² and the total perimeter is 38.4 cm, including 12.8 cm along the inner hole.

Certified measurements (1:1 scale)

Net area
39.2 cm²
Total perimeter
38.4 cm
Outer boundary
25.6 cm
Hole boundaries
12.8 cm
Bounding box
7.73 × 7.73 cm
Basic shapes
2
Open in TypeLab 2D

Step-by-step decomposition

  1. 1.Baseregular octagon with side 3.2 cm49.44 cm²
  2. 2.−square with side 3.2 cm10.24 cm²

Area of each basic shape before the Boolean composition.

How to find the area

Area formula: A = 2(1+√2)·l² − l² = (1+2√2)·l²

Split the figure into basic shapes, find each area, add the joined parts and subtract the cut-outs: A = 49.44 − 10.24 = 39.2 cm².

Editable in PowerPoint & Office

The .PPTX file contains native DrawingML shapes: outlines, dimensions and labels stay separate objects you can recolor and edit in PowerPoint, Keynote and Google Slides. The .SVG file is pure vector art at 1:1 scale on an A4 sheet, ready for print, LaTeX and textbook layout.

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