Convert both quantities to the same unit, then simplify the ratio.<br><br>
&bull; 1 m = 100 cm<br>
&bull; Ratio 25 cm : 1 m = 25 : 100<br>
&bull; Simplify: divide both by their HCF, 25.<br>
&bull; 25 ÷ 25 = 1, 100 ÷ 25 = 4<br>
&bull; Ratio = 1 : 4<br><br>
Final Answer: 1:4