The area of a regular pentagon looks about twice as a big as the pentangle star drawn within it. Is it?
Find the area of the shaded region created by the two overlapping triangles in terms of a and b?
Two right-angled triangles are connected together as part of a structure. An object is dropped from the top of the green triangle where does it pass the base of the blue triangle?
Straight lines are drawn from each corner of a square to the mid points of the opposite sides. Express the area of the octagon that is formed at the centre as a fraction of the area of the square.
Triangle ABC is equilateral. D, the midpoint of BC, is the centre of the semi-circle whose radius is R which touches AB and AC, as well as a smaller circle with radius r which also touches AB and AC. . . .
Two ladders are propped up against facing walls. The end of the first ladder is 10 metres above the foot of the first wall. The end of the second ladder is 5 metres above the foot of the second. . . .
Take any rectangle ABCD such that AB > BC. The point P is on AB and Q is on CD. Show that there is exactly one position of P and Q such that APCQ is a rhombus.
Construct a line parallel to one side of a triangle so that the triangle is divided into two equal areas.
Can you work out the fraction of the original triangle that is covered by the inner triangle?
Read all about the number pi and the mathematicians who have tried to find out its value as accurately as possible.
A ladder 3m long rests against a wall with one end a short distance from its base. Between the wall and the base of a ladder is a garden storage box 1m tall and 1m high. What is the maximum distance. . . .
A trapezium is divided into four triangles by its diagonals. Can you work out the area of the trapezium?
Which is a better fit, a square peg in a round hole or a round peg in a square hole?
A circle of radius r touches two sides of a right angled triangle, sides x and y, and has its centre on the hypotenuse. Can you prove the formula linking x, y and r?
Move the point P to see how P' moves. Then use your insights to calculate a missing length.
The diagram shows a regular pentagon with sides of unit length. Find all the angles in the diagram. Prove that the quadrilateral shown in red is a rhombus.
The diagonals of a trapezium divide it into four parts. Can you create a trapezium where three of those parts are equal in area?
What angle is needed for a ball to do a circuit of the billiard table and then pass through its original position?
Points P, Q, R and S each divide the sides AB, BC, CD and DA respectively in the ratio of 2 : 1. Join the points. What is the area of the parallelogram PQRS in relation to the original rectangle?
The Earth is further from the Sun than Venus, but how much further? Twice as far? Ten times?
Rectangle PQRS has X and Y on the edges. Triangles PQY, YRX and XSP have equal areas. Prove X and Y divide the sides of PQRS in the golden ratio.
Two buses leave at the same time from two towns Shipton and Veston on the same long road, travelling towards each other. At each mile along the road are milestones. The buses' speeds are constant. . . .
What is the ratio of the area of a square inscribed in a semicircle to the area of the square inscribed in the entire circle?
Can you find an efficent way to mix paints in any ratio?
Four jewellers share their stock. Can you work out the relative values of their gems?
Can you work out how to produce different shades of pink paint?
We use statistics to give ourselves an informed view on a subject of interest. This problem explores how to scale countries on a map to represent characteristics other than land area.
If the sides of the triangle in the diagram are 3, 4 and 5, what is the area of the shaded square?
Find the ratio of the outer shaded area to the inner area for a six pointed star and an eight pointed star.
Two perpendicular lines lie across each other and the end points are joined to form a quadrilateral. Eight ratios are defined, three are given but five need to be found.
What's the most efficient proportion for a 1 litre tin of paint?
The large rectangle is divided into a series of smaller quadrilaterals and triangles. Can you untangle what fractional part is represented by each of the ten numbered shapes?
A right circular cone is filled with liquid to a depth of half its vertical height. The cone is inverted. How high up the vertical height of the cone will the liquid rise?
If it takes four men one day to build a wall, how long does it take 60,000 men to build a similar wall?
Two motorboats travelling up and down a lake at constant speeds leave opposite ends A and B at the same instant, passing each other, for the first time 600 metres from A, and on their return, 400. . . .
At the beginning of the night three poker players; Alan, Bernie and Craig had money in the ratios 7 : 6 : 5. At the end of the night the ratio was 6 : 5 : 4. One of them won $1 200. What were the. . . .
A cyclist and a runner start off simultaneously around a race track each going at a constant speed. The cyclist goes all the way around and then catches up with the runner. He then instantly turns. . . .
A Sudoku with clues as ratios.
Two boats travel up and down a lake. Can you picture where they will cross if you know how fast each boat is travelling?
Which dilutions can you make using 10ml pipettes and 100ml measuring cylinders?
Which exact dilution ratios can you make using only 2 dilutions?
Imagine you were given the chance to win some money... and imagine you had nothing to lose...
How long will it take Mary and Nigel to wash an elephant if they work together?
One night two candles were lit. Can you work out how long each candle was originally?
A farmer is supplying a mix of seeds, nuts and dried apricots to a manufacturer of crunchy cereal bars. What combination of ingredients costing £5 per kg could he supply?
Scientists often require solutions which are diluted to a particular concentration. In this problem, you can explore the mathematics of simple dilutions
A garrison of 600 men has just enough bread ... but, with the news that the enemy was planning an attack... How many ounces of bread a day must each man in the garrison be allowed, to hold out 45. . . .
My recipe is for 12 cakes - how do I change it if I want to make a different number of cakes?
In a race the odds are: 2 to 1 against the rhinoceros winning and 3 to 2 against the hippopotamus winning. What are the odds against the elephant winning if the race is fair?
A Sudoku with clues as ratios.