Find the ratio of the circumference of a circle with radius 1.125 to the circumference of a circle with diameter 2.25. Express your answer in the form $a:b$ where $a$ and $b$ are relatively prime positive integers.
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Find the ratio of the circumference of a circle with radius 1.125 to the circumference of a circle with diameter 2.25. Express your answer in the form $a:b$ where $a$ and $b$ are relatively prime positive integers.
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
1:1
Find the ratio of the circumference of a circle with radius 1.125 to the circumference of a circle with diameter 2.25. Express your answer in the form $a:b$ where $a$ and $b$ are relatively prime positive integers.
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