To find the radius of the original circle before dilation, you divide the radius of the dilated circle by the scale factor.
Given:
- Scale factor = 15
- Radius of the dilated circle = 18 cm
To find the radius of the original circle:
\[ \text{Radius of original circle} = \frac{\text{Radius of dilated circle}}{\text{Scale factor}} = \frac{18 \text{ cm}}{15} = 1.2 \text{ cm} \]
None of the provided choices match the result of 1.2 cm, which indicates that there might be an issue with the answer choices. Could you double-check the options provided?