Other tags that relate to Secants Interactivity
2D shapes and their properties. Ratio and proportion. Symmetry. Circle properties and circle theorems. Quadrilaterals. Reflections. Angles - points, lines and parallel lines. Area - triangles, quadrilaterals, compound shapes. Dynamic geometry. Similarity and congruence.There are 72 results
Broad Topics > Fractions, Decimals, Percentages, Ratio and Proportion > Ratio and proportion
Fractions Rectangle
Age 11 to 14 Challenge Level:
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?
Trapezium Four
Age 14 to 16 Challenge Level:
The diagonals of a trapezium divide it into four parts. Can you create a trapezium where three of those parts are equal in area?
Orbiting Billiard Balls
Age 14 to 16 Challenge Level:
What angle is needed for a ball to do a circuit of the billiard table and then pass through its original position?
Points in Pairs
Age 14 to 16 Challenge Level:
Move the point P to see how P' moves. Then use your insights to calculate a missing length.
The Rescaled Map
Age 14 to 16 Challenge Level:
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.
From All Corners
Age 14 to 16 Challenge Level:
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.
At a Glance
Age 14 to 16 Challenge Level:
The area of a regular pentagon looks about twice as a big as the pentangle star drawn within it. Is it?
Rhombus in Rectangle
Age 14 to 16 Challenge Level:
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.
Triangle in a Triangle
Age 14 to 16 Challenge Level:
Can you work out the fraction of the original triangle that is covered by the inner triangle?
Pi, a Very Special Number
Age 7 to 14
Read all about the number pi and the mathematicians who have tried to find out its value as accurately as possible.
A Shade Crossed
Age 14 to 16 Challenge Level:
Find the area of the shaded region created by the two overlapping triangles in terms of a and b?
Wedge on Wedge
Age 14 to 16 Challenge Level:
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?
A Scale for the Solar System
Age 14 to 16 Challenge Level:
The Earth is further from the Sun than Venus, but how much further? Twice as far? Ten times?
Arrh!
Age 14 to 16 Challenge Level:
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
Age 14 to 16 Challenge Level:
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. . . .
Square Pegs
Age 11 to 14 Challenge Level:
Which is a better fit, a square peg in a round hole or a round peg in a square hole?
Same Height
Age 14 to 16 Challenge Level:
A trapezium is divided into four triangles by its diagonals. Can you work out the area of the trapezium?
Half a Triangle
Age 14 to 16 Challenge Level:
Construct a line parallel to one side of a triangle so that the triangle is divided into two equal areas.
Sitting Pretty
Age 14 to 16 Challenge Level:
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?
Number Lines in Disguise
Age 7 to 14 Challenge Level:
Some of the numbers have fallen off Becky's number line. Can you figure out what they were?
Tray Bake
Age 11 to 14 Challenge Level:
My recipe is for 12 cakes - how do I change it if I want to make a different number of cakes?
Burning Down
Age 14 to 16 Challenge Level:
One night two candles were lit. Can you work out how long each candle was originally?
Mixing More Paints
Age 14 to 16 Challenge Level:
Can you find an efficent way to mix paints in any ratio?
Star Gazing
Age 14 to 16 Challenge Level:
Find the ratio of the outer shaded area to the inner area for a six pointed star and an eight pointed star.
Mixing Paints
Age 11 to 14 Challenge Level:
Can you work out how to produce different shades of pink paint?
Cereal Mix
Age 11 to 14 Challenge Level:
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?
Slippage
Age 14 to 16 Challenge Level:
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. . . .
Golden Thoughts
Age 14 to 16 Challenge Level:
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.
Conical Bottle
Age 14 to 16 Challenge Level:
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?
Semi-square
Age 14 to 16 Challenge Level:
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?
Washing Elephants
Age 11 to 14 Short Challenge Level:
How long will it take Mary and Nigel to wash an elephant if they work together?
Pent
Age 14 to 18 Challenge Level:
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.
Eight Ratios
Age 14 to 16 Challenge Level:
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.
Ratio or Proportion?
Age 7 to 14
An article for teachers which discusses the differences between ratio and proportion, and invites readers to contribute their own thoughts.
Ratios and Dilutions
Age 14 to 16 Challenge Level:
Scientists often require solutions which are diluted to a particular concentration. In this problem, you can explore the mathematics of simple dilutions
Exact Dilutions
Age 14 to 16 Challenge Level:
Which exact dilution ratios can you make using only 2 dilutions?
Bus Stop
Age 14 to 16 Challenge Level:
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. . . .
Tin Tight
Age 14 to 16 Challenge Level:
What's the most efficient proportion for a 1 litre tin of paint?
The Fastest Cyclist
Age 14 to 16 Challenge Level:
Andy is desperate to reach John o'Groats first. Can you devise a winning race plan?
Retiring to Paradise
Age 11 to 14 Challenge Level:
When Charlie retires, he's looking forward to the quiet life, whereas Alison wants a busy and exciting retirement. Can you advise them on where they should go?
Gift of Gems
Age 14 to 16 Challenge Level:
Four jewellers share their stock. Can you work out the relative values of their gems?
Rati-o
Age 11 to 14 Challenge Level:
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?
Rule of Three
Age 11 to 14 Challenge Level:
If it takes four men one day to build a wall, how long does it take 60,000 men to build a similar wall?
Oh for the Mathematics of Yesteryear
Age 11 to 14 Challenge Level:
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. . . .
Do Unto Caesar
Age 11 to 14 Challenge Level:
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. . . .
Racing Odds
Age 11 to 14 Challenge Level:
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?
How Big?
Age 11 to 14 Challenge Level:
If the sides of the triangle in the diagram are 3, 4 and 5, what is the area of the shaded square?
Zin Obelisk
Age 11 to 14 Challenge Level:
In the ancient city of Atlantis a solid rectangular object called a Zin was built in honour of the goddess Tina. Your task is to determine on which day of the week the obelisk was completed.
NRICH is part of the family of activities in the Millennium Mathematics Project.