1. **State the problem:** Two arcs of the same circle subtend angles in the ratio 3:5. The difference of their arc lengths is 16\pi cm. We need to find the radius of the circle.
2. **Recall the formula for arc length:** The length $L$ of an arc subtending an angle $\theta$ (in radians) in a circle of radius $r$ is given by:
$$L = r\theta$$
3. **Set up variables:** Let the angles subtended by the two arcs be $3x$ and $5x$ radians respectively.
4. **Express arc lengths:**
- Arc length 1: $L_1 = r \times 3x = 3rx$
- Arc length 2: $L_2 = r \times 5x = 5rx$
5. **Use the difference of arc lengths:**
$$L_2 - L_1 = 16\pi$$
Substitute the expressions:
$$5rx - 3rx = 16\pi$$
$$\cancel{r}x(5 - 3) = 16\pi$$
$$2rx = 16\pi$$
6. **Simplify to find $rx$:**
$$rx = \frac{16\pi}{2} = 8\pi$$
7. **Use the fact that the total angle is $3x + 5x = 8x$ radians, which must be less than or equal to $2\pi$ for a circle:**
Since the arcs are parts of the same circle, the total angle $8x$ should be $2\pi$ (full circle) or less.
Assuming the arcs cover the full circle:
$$8x = 2\pi$$
$$x = \frac{2\pi}{8} = \frac{\pi}{4}$$
8. **Find the radius $r$ using $rx = 8\pi$:**
$$r \times \frac{\pi}{4} = 8\pi$$
Divide both sides by $\pi$:
$$r \times \frac{1}{4} = 8$$
$$\cancel{r} \times \frac{1}{4} = 8$$
$$r = 8 \times 4 = 32$$
**Final answer:** The radius of the circle is $\boxed{32}$ cm.
Circle Radius C60C65
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