mscroggs.co.uk
mscroggs.co.uk

subscribe

Advent calendar 2019

2 December

You have 15 sticks of length 1cm, 2cm, ..., 15cm (one of each length). How many triangles can you make by picking three sticks and joining their ends?
Note: Three sticks (eg 1, 2 and 3) lying on top of each other does not count as a triangle.
Note: Rotations and reflections are counted as the same triangle.

Show answer

Archive

Show me a random puzzle
 Most recent collections 

Advent calendar 2020

Advent calendar 2019

Sunday Afternoon Maths LXVII

Coloured weights
Not Roman numerals

Advent calendar 2018


List of all puzzles

Tags

clocks circles routes spheres coins games sport integration 3d shapes planes ellipses regular shapes digits triangle numbers addition square roots tiling sums mean calculus squares balancing volume menace multiples range sum to infinity factorials pascal's triangle wordplay crossnumber 2d shapes christmas averages numbers crosswords coordinates chess chalkdust crossnumber chocolate proportion functions grids bases median crossnumbers folding tube maps scales perfect numbers shape indices unit fractions factors hexagons partitions star numbers doubling probability odd numbers colouring arrows rugby integers parabolas dates surds shapes speed square numbers ave money books perimeter cryptic crossnumbers advent trigonometry algebra prime numbers digital clocks area fractions sequences multiplication the only crossnumber taxicab geometry division combinatorics irreducible numbers angles polygons time cards probabilty dice quadratics complex numbers lines elections differentiation dodecagons palindromes number rectangles gerrymandering triangles percentages quadrilaterals remainders people maths graphs cube numbers products dominos means symmetry geometry logic cryptic clues floors

Archive

Show me a random puzzle
▼ show ▼
© Matthew Scroggs 2012–2021