calculate temperature

hello there
my name is jef and i have a little problem

i have an assignment for school with arduino
i have to make someting that shows the temperatur in visual basic

so i choice for arduino to get te temperature into the computer
and everyting works just fine except 1 thing

i don't know how to calculate the temperatur from voltage

this is the datasheet of my sensor (datascheet)
i use the MA100100GG103A

i have a resistor of 4 480 ohm (it's an ntc)

and 1 little thing to make it harder i also have an transmitter on the same 5v output
(i can put it on a battery probably will put it on a batery)

can someone help me to get the formule

Since this is a school assignment, you should do some research and learn how these things work. Google "arduino thermistor temperature" and (at least in my locale) the top three hits are tutorials on how to measure temperature using a thermistor.