length, area and volume factors

it's probably helpful if students appreciate what happens to the overall size of a shape if you e.g. double in two or three directions*

a ppt is here

see also big sprouts and Frodo Baggins
and wombats and diprotodons 

*an estimate of the adult height of a male is obtained by doubling their height when they are 2 years old
for a female height estimate, it is double their height when they are 18 months old

big sprouts and Frodo Baggins

larger than usual sprouts were available this year (milder winter)
I've changed the numbers reported by a newspaper slightly
[thanks to mathspad]

Elijah Wood played the film role Frodo Baggins

yin yang

the intervals across the diameter are equal
show that the differently coloured areas are the same

wombats and diprotodons

full skeletons of a giant marsupial, the diprotodon have been discovered in Australia
they were calculated to be around 3.2 m long
they are related to the wombat

in 2012, a significant group of about 40 diprotodon remains was found in South-West Queensland

a male wombat grows to around 1 metre long and weighs 28kg





using a length ratio of 1 : 3.8 estimate the weight of the diprotodon


(1 tonne = 1000kg)