mscroggs.co.uk
mscroggs.co.uk

subscribe

Puzzles

Is it equilateral?

In the diagram below, \(ABDC\) is a square. Angles \(ACE\) and \(BDE\) are both 75°.
Is triangle \(ABE\) equilateral? Why/why not?

Show answer

17 December

The number of degrees in one internal angle of a regular polygon with 360 sides.

Ticking clock

Is there a time of day when the hands of an analogue clock (one with a second hand that moves every second instead of moving continuously) will all be 120° apart?

Show answer & extension

Tags: angles, time

Dodexagon

In the diagram, B, A, C, D, E, F, G, H, I, J, K and L are the vertices of a regular dodecagon and B, A, M, N, O and P are the vertices of a regular hexagon.
Show that A, M and E lie on a straight line.

Show answer & extension

Three squares

Source: Numberphile
The diagram shows three squares with diagonals drawn on and three angles labelled.
What is the value of \(\alpha+\beta+\gamma\)?

Show answer & extension

Archive

Show me a random puzzle
 Most recent collections 

Sunday Afternoon Maths LXVII

Coloured weights
Not Roman numerals

Advent calendar 2018

Sunday Afternoon Maths LXVI

Cryptic crossnumber #2

Sunday Afternoon Maths LXV

Cryptic crossnumber #1
Breaking Chocolate
Square and cube endings

List of all puzzles

Tags

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

Archive

Show me a random puzzle
▼ show ▼
© Matthew Scroggs 2019