![Babylon numbers](/sites/default/files/styles/medium/public/thumbnails/content-id-6001-icon.jpg?itok=rgLOeN_d)
Pythagoras' theorem
![Babylon numbers](/sites/default/files/styles/medium/public/thumbnails/content-id-6001-icon.jpg?itok=rgLOeN_d)
![The Fire-fighter's Car Keys](/sites/default/files/styles/medium/public/thumbnails/content-id-5891-icon.png?itok=yZvY93at)
problem
The Fire-fighter's Car Keys
A fire-fighter needs to fill a bucket of water from the river and
take it to a fire. What is the best point on the river bank for the
fire-fighter to fill the bucket ?.
![Under the Ribbon](/sites/default/files/styles/medium/public/thumbnails/content-id-5889-icon.png?itok=F-REVoQx)
problem
Under the Ribbon
A ribbon is nailed down with a small amount of slack. What is the
largest cube that can pass under the ribbon ?
![Interior Squares](/sites/default/files/styles/medium/public/thumbnails/content-id-5710-icon.png?itok=_FPXixVU)
problem
Interior Squares
Calculate the ratio of areas of these squares which are inscribed inside a semi-circle and a circle.
![Common Tangent](/sites/default/files/styles/medium/public/thumbnails/content-id-5685-icon.png?itok=PQ2pQ2Nb)
problem
Common Tangent
Two circles touch, what is the length of the line that is a tangent to both circles?
![Nicely Similar](/sites/default/files/styles/medium/public/thumbnails/content-id-5635-icon.png?itok=H87VLq-O)
problem
Nicely Similar
If the hypotenuse (base) length is 100cm and if an extra line
splits the base into 36cm and 64cm parts, what were the side
lengths for the original right-angled triangle?
![Spherical triangles on very big spheres](/sites/default/files/styles/medium/public/thumbnails/content-id-5623-icon.jpg?itok=flfA5PWp)
problem
Spherical triangles on very big spheres
Shows that Pythagoras for Spherical Triangles reduces to
Pythagoras's Theorem in the plane when the triangles are small
relative to the radius of the sphere.
![Where is the dot?](/sites/default/files/styles/medium/public/thumbnails/content-id-5615-icon.jpg?itok=tWV7bskh)
problem
Where is the dot?
A dot starts at the point (1,0) and turns anticlockwise. Can you estimate the height of the dot after it has turned through 45 degrees? Can you calculate its height?
![Right Angled Possibilities](/sites/default/files/styles/medium/public/thumbnails/content-id-5025-icon.png?itok=-IgpNCPP)
problem
Right Angled Possibilities
If two of the sides of a right-angled triangle are 5cm and 6cm long, how many possibilities are there for the length of the third side?
![Walk the Plank](/sites/default/files/styles/medium/public/thumbnails/content-id-4885-icon.png?itok=amgP1oTF)
problem
Walk the Plank
A rectangular plank fits neatly inside a square frame when placed diagonally. What is the length of the plank?