Other tags that relate to Secants Interactivity
Quadrilaterals. Ratio and proportion. Rotations. Area - triangles, quadrilaterals, compound shapes. GeoGebra. Dynamic geometry. 2D shapes and their properties. Symmetry. Reflections. Regular polygons and circles.There are 72 results
Broad Topics > Fractions, Decimals, Percentages, Ratio and Proportion > Ratio and proportion
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?
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.
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.
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.
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?
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?
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.
Mixing Paints
Age 11 to 14
Challenge Level
Can you work out how to produce different shades of pink paint?
Mixing More Paints
Age 14 to 16
Challenge Level
Can you find an efficent way to mix paints in any ratio?
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?
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.
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. . . .
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.
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?
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?
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?
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.
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?
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?
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?
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.
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. . . .
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?
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.
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.
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?
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.
Investigating the Dilution Series
Age 14 to 16
Challenge Level
Which dilutions can you make using only 10ml pipettes?
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?
Mixed up Mixture
Age 14 to 16
Challenge Level
Can you fill in the mixed up numbers in this dilution calculation?
Contact
Age 14 to 16
Challenge Level
A circular plate rolls in contact with the sides of a rectangular tray. How much of its circumference comes into contact with the sides of the tray when it rolls around one circuit?
Equal Temperament
Age 14 to 16
Challenge Level
The scale on a piano does something clever : the ratio (interval) between any adjacent points on the scale is equal. If you play any note, twelve points higher will be exactly an octave on.
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?
Speeding Boats
Age 14 to 16
Challenge Level
Two boats travel up and down a lake. Can you picture where they will cross if you know how fast each boat is travelling?
Nutrition and Cycling
Age 14 to 16
Challenge Level
Andy wants to cycle from Land's End to John o'Groats. Will he be able to eat enough to keep him going?
Exact Dilutions
Age 14 to 16
Challenge Level
Which exact dilution ratios can you make using only 2 dilutions?
Dilution Series Calculator
Age 14 to 16
Challenge Level
Which dilutions can you make using 10ml pipettes and 100ml measuring cylinders?
Toad in the Hole
Age 11 to 14
Challenge Level
Is it cheaper to cook a meal from scratch or to buy a ready meal? What difference does the number of people you're cooking for make?
Straw Scaffold
Age 11 to 14
Challenge Level
Build a scaffold out of drinking-straws to support a cup of water
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
Tin Tight
Age 14 to 16
Challenge Level
What's the most efficient proportion for a 1 litre tin of paint?
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?
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?
NRICH is part of the family of activities in the Millennium Mathematics Project.