$a)$

$\frac{9}{72}=\frac{1}{8}$

$\frac{1}{8}\cdot 100\%=12\frac{1}{2}\%$  

$\frac{4}{72}=\frac{1}{18}$

$\frac{1}{18}\cdot 100\%=5\frac{5}{9}\%$     

 

$\frac{18}{72}=\frac{1}{4}$

$\frac{1}{4}\cdot 100\%=25\%$

 

$\frac{27}{72}=\frac{3}{8}$

$\frac{3}{8}\cdot 100\%=37\frac{1}{2}\%$

 

$\frac{72}{72}=1$

$1\cdot 100\%=100\%$

 

$\frac{108}{72}=\frac{3}{2}$

$\frac{3}{2}\cdot 100\%=150\%$

 

$\frac{144}{72}=2$

$2\cdot 100\%=200\%$

 

$b)$

$1m=100cm$

$\frac{1}{100}\cdot 100\%=1\%$

 

$\frac{15}{100}=\frac{3}{20}$

$\frac{3}{20}\cdot 100\%=15\%$

 

$\frac{90}{100}=\frac{9}{10}$

$\frac{9}{10}\cdot 100\%=90\%$

 

$\frac{25}{100}=\frac{1}{4}$

$\frac{1}{4}\cdot 100\%=25\%$

 

$\frac{50}{100}=\frac{1}{2}$

$\frac{1}{2}\cdot 100\%=50\%$

 

1m=1000mm

 

$\frac{1}{1000}\cdot 100\%=0,1\%$

 

$c)$

$1km=1000m$

$\frac{1}{1000}\cdot 100\%=0,1\%$

 

$\frac{350}{1000}=\frac{35}{100}$

$\frac{35}{100}\cdot 100\%=35\%$

 

$\frac{1000}{1000}=1$

$1\cdot 100\%=100$

 

$\frac{840}{1000}=\frac{84}{100}$

$\frac{84}{100}\cdot 100\%=84\%$

 

$\frac{100}{1000}=\frac{10}{100}$

$\frac{10}{100}\cdot 100\%=10\%$

 

$1km=100000cm$

$\frac{1}{100000}\cdot 100\%=0,001\%$

 

$\frac{50}{100000}=\frac{5}{10000}$

$\frac{5}{10000}\cdot 100\%=0,05\%$