mscroggs.co.uk
mscroggs.co.uk

subscribe

Puzzles

Cutting corners

The diagram below shows a triangle \(ABC\). The line \(CE\) is perpendicular to \(AB\) and the line \(AD\) is perpedicular to \(BC\).
The side \(AC\) is 6.5cm long and the lines \(CE\) and \(AD\) are 5.6cm and 6.0cm respectively.
How long are the other two sides of the triangle?

Show answer

Equal side and angle

In the diagram shown, the lengths \(AD = CD\) and the angles \(ABD=CBD\).
Prove that the lengths \(AB=BC\).

Show answer

Arctan

Prove that \(\arctan(1)+\arctan(2)+\arctan(3)=\pi\).

Show answer & extension

Sine

A sine curve can be created with five people by giving the following instructions to the five people:
A. Stand on the spot.
B. Walk around A in a circle, holding this string to keep you the same distance away.
C. Stay in line with B, staying on this line.
D. Walk in a straight line perpendicular to C's line.
E. Stay in line with C and D. E will trace the path of a sine curve as shown here:
What instructions could you give to five people to trace a cos(ine) curve?
What instructions could you give to five people to trace a tan(gent) curve?

Show answer & extension

arccos + arcsin

What is the value of \(\arccos(x) + \arcsin(x)\)?

Show answer & extension

Archive

Show me a random puzzle
 Most recent collections 

Advent calendar 2024

Advent calendar 2023

Advent calendar 2022

Advent calendar 2021


List of all puzzles

Tags

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

Archive

Show me a random puzzle
▼ show ▼
© Matthew Scroggs 2012–2025