Find the ratio of `30 cm` to `290 mm`.

Options

A. `30:29`
B. `20:19`
C. `25:29`
D. `39:28`

Answer

To find the ratio of 30 cm to 290 mm, we can follow these steps:

### Step 1: Convert the units
First, we need to convert 290 mm into centimeters because the two quantities should be in the same unit for comparison. We know that 1 cm = 10 mm.

To convert mm to cm, we divide by 10:
\[ 290 \text{ mm} = \frac{290}{10} \text{ cm} = 29 \text{ cm} \]

### Step 2: Set up the ratio
Now we can set up the ratio of 30 cm to 29 cm:
\[ \text{Ratio} = \frac{30 \text{ cm}}{29 \text{ cm}} \]

### Step 3: Simplify the ratio
The units (cm) will cancel out, so we are left with:
\[ \text{Ratio} = \frac{30}{29} \]

### Step 4: Write the ratio in standard form
We can express this as:
\[ 30 : 29 \]

### Final Answer
Thus, the ratio of 30 cm to 290 mm is:
\[ \text{Ratio} = 30 : 29 \]

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