Middle school · TypeLab 2D
Concave Lens Block
Concave Lens Block: a composite plane figure made of a rectangle 8 × 5.2 cm, minus a semicircle of radius 2.6 cm, minus a semicircle of radius 2.6 cm. It is a classic middle school geometry problem (“Cutouts & Benchmarks”). The net area is 20.38 cm² and the total perimeter is 32.33 cm.
Certified measurements (1:1 scale)
- Net area
- 20.38 cm²
- Total perimeter
- 32.33 cm
- Bounding box
- 8 × 5.2 cm
- Basic shapes
- 3
Step-by-step decomposition
- 1.Baserectangle 8 × 5.2 cm41.6 cm²
- 2.−semicircle of radius 2.6 cm10.62 cm²
- 3.−semicircle of radius 2.6 cm10.62 cm²
Area of each basic shape before the Boolean composition.
How to find the area
Area formula: A = b·h − π·(h/2)²
Split the figure into basic shapes, find each area, add the joined parts and subtract the cut-outs: A = 41.6 − 10.62 − 10.62 = 20.38 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.
