Counting Figures Level 2 Reasoning Practice: Triangles, Squares and Lines
This Level 2 Counting Figures set is medium-level reasoning practice. It checks whether you can count every triangle, square and rectangle inside a figure, including overlapping shapes, and find the minimum number of straight lines needed to draw it. On Aptitude360, every question has a worked solution that breaks the figure down piece by piece.
What this Counting Figures set asks you to count
- Triangles formed by inner and crossing lines
- Squares of every size within a figure
- Rectangles, with squares included
- Minimum number of straight lines needed to draw a figure
Counting figures formulas for standard patterns
- Squares in an \( n \times n \) grid: \( \dfrac{n(n+1)(2n+1)}{6} \)
- Rectangles in an \( m \times n \) grid: \( \dfrac{m(m+1)}{2}\times\dfrac{n(n+1)}{2} \)
- Triangles when \( n \) lines (both sides included) join the apex to the base: \( \dfrac{n(n-1)}{2} \)
Core ideas for accurate shape counting
- Labelling every corner and intersection point with a letter
- Separating single-piece shapes from those formed by combining pieces
- Treating collinear segments as one straight line
Revision tips for figure counting questions
- Count the smallest shapes first, then shapes made of two, three or more pieces
- Split a complex figure into a known pattern and apply its formula before adding extra shapes
- For straight-line questions, count horizontal, vertical and slanting lines separately
Who this Level 2 set suits
Reasoning aspirants who know the basics of figure counting and want medium-level practice before denser figures.