Convert 3 3/5 to Improper Fraction, convert 0.45 to a Fraction in its Lowest Form, Express 75% as a percentage, Convert 85% to a Fraction in its Lowest form, Arrange in ascending order, Express 3/8 as decimal.

$$
3 \frac{3}{5} = \frac{(3 \times 5) + 3}{5}
$$

$$
3 \frac{3}{5} = \frac{15 + 3}{5} = \frac{18}{5}
$$
The improper fraction is $\boxed{\frac{18}{5}}$.

$$
0.45 = \frac{45}{100}
$$

$$
\frac{45 \div 5}{100 \div 5} = \frac{9}{20}
$$
The fraction in its lowest form is $\boxed{\frac{9}{20}}$.

$$
\frac{7}{50} \times 100\%
$$

$$
\frac{7}{50} \times 100\% = 7 \times \frac{100}{50}\% = 7 \times 2\% = 14\%
$$
$\frac{7}{50}$ as a percentage is $\boxed{14\%}$.

$$
85\% = \frac{85}{100}
$$

$$
\frac{85 \div 5}{100 \div 5} = \frac{17}{20}
$$
The fraction in its lowest form is $\boxed{\frac{17}{20}}$.

$$
\frac{3}{5} = \frac{3 \times 2}{5 \times 2} = \frac{6}{10}
$$
$$
\frac{7}{10}
$$
$$
\frac{1}{2} = \frac{1 \times 5}{2 \times 5} = \frac{5}{10}
$$
$$
\frac{4}{5} = \frac{4 \times 2}{5 \times 2} = \frac{8}{10}
$$

$$
\frac{5}{10}, \frac{6}{10}, \frac{7}{10}, \frac{8}{10}
$$

$$
\frac{1}{2}, \frac{3}{5}, \frac{7}{10}, \frac{4}{5}
$$
The fractions in ascending order are $\boxed{\frac{1}{2}, \frac{3}{5}, \frac{7}{10}, \frac{4}{5}}$.

$$
\frac{3}{8} = 3 \div 8
$$

$$
3 \div 8 = 0.375
$$
$\frac{3}{8}$ as a decimal is $\boxed{0.375}$.