`a)`
`@1m^2=100dm^2=10000cm^2=1000000mm^2`
GT: `1m^2=100dm^2`
`1dm^2=100cm^2`
`1cm^2=100mm^2`
`@1ha=10000m^2`
`@1km^2=100ha=1000000m^2`
`b)`
`@1m^2=0,01dam^2`
`@1ha=0,01km^2`
`@1m^2=0,0001hm^2=0,0001ha`
GT: `hm^2=ha`
`@4ha=0,04km^2`
GT: `1ha=0,01km^2`
`@1m^2=0,000001km^2`