1. **Problem statement:** The ratio of the radii of two circles is given as 8 : 9. We need to find the ratio of their circumferences and the ratio of their areas.
2. **Formulas used:**
- Circumference of a circle: $$C = 2\pi r$$
- Area of a circle: $$A = \pi r^2$$
3. **Ratio of circumferences:**
Given the radii ratio $$r_1 : r_2 = 8 : 9$$
The ratio of circumferences is:
$$\frac{C_1}{C_2} = \frac{2\pi r_1}{2\pi r_2} = \frac{r_1}{r_2} = \frac{8}{9}$$
4. **Ratio of areas:**
Using the area formula:
$$\frac{A_1}{A_2} = \frac{\pi r_1^2}{\pi r_2^2} = \frac{r_1^2}{r_2^2} = \frac{8^2}{9^2} = \frac{64}{81}$$
5. **Final answers:**
- Ratio of circumferences = 8 : 9
- Ratio of areas = 64 : 81
These ratios show that circumference ratio is the same as the radius ratio, while the area ratio is the square of the radius ratio.
Circle Ratios Cac9Cd
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