At one point in 2011, there were approximately 2.1 billion internet users worldwide. if approximately 9/40 of the users lived in europe, estimate the number of internet users in europe at this time.

Estimating the number of internet users in Europe by multiplying the ratio with the whole internet users
users in Europe = 9/40 × 2.1 billion
users in Europe = 9/40 × 2,100 million
users in Europe = (9 × 2,100)/40  million
users in Europe = 18,900/40 million
users in Europe = 472.5 million

The number of internet users in Europe is approximately 472.5 million at this time