Answer
(a) $5.6$
(b) $5.65$
(c) $5.6491$
Work Step by Step
Given: $5.64908$
(a) The tenths digit $6$ is followed by a $4$. Thus, retain to $6$ and drop the rest of the decimals to its right to obtain:
$5.6$
(b) The hundredths digit $4$ is followed by a $9$. Thus, round up to $5$ and drop the rest of the decimals to its right to obtain:
$5.65$
(c) The ten-thousandths digit $0$ is followed by an $8$. Thus, round up to $1$ and drop the rest of the digits to its right to obtain:
$5.6491$