How many other triangles can you make with 11 sticks?
Investigate all the triangles that you can make with different numbers of sticks.
Record your […]
Find the total area of the two triangles by two different methods if ACD and BCE are straight lines .
What are the lengths PC and CQ?
The triangles are re-drawn keeping the total area the same and keeping the distances between the green parallel lines as 3 cm and BD = 4 cm.
What do you notice about this shape?
Describe the shapes of the tangram pieces.
What is the same and what is different about the shapes of the tangram pieces?
Make a pattern of your own using all 7 pieces.
If you also know that AB and CD are parallel which angles can you find?
What extra information do you need to find all the numbered angles?
What do you notice? Why does this happen? Will it […]
Using what you know about angles and parallel lines prove that the angles of the triangle add up to 180 degrees.
Four rods are hinged at their ends to form a convex quadrilateral with sides of length 3, 4, 5 and 6 (in that order). Investigate the different shapes that the quadrilateral can take if the polygon is always convex.
How do the angles change as the bendy quad changes shape?
Can any […]
The line RS is a tangent at P to the circle centre O and radius 1 unit.
Find the lengths OQ, PQ, PS, OS, OR and RP.
If OS and OR lie on the coordinate axes, what are the coordinates […]
The diagram shows three angles a, b and c.
How many ways can you prove that a + b = c?
What other interesting properties can you find?
When this activity was originally published on NRICH, two boys from Madras School in St Andrew’s, Scotland sent […]