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

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

Archive

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