1. **Problem Statement:**
Given two equal circles with perimeter 360 m each, intersecting at points A, B, C, and D such that AC = DB and center O is the intersection of lines AD and BC.
We need to find:
(i) The value of angle $D\hat{O}C = A\hat{O}B$.
(ii) The length of $OA = OB = OC = OD$.
(iii) The length of segment $AB$ given that $AB$ equals $DC$.
2. **Step 1: Understanding the circles and perimeter**
Each circle has perimeter (circumference) $C = 360$ m.
The formula for circumference of a circle is:
$$C = 2\pi r$$
where $r$ is the radius.
So,
$$360 = 2\pi r \implies r = \frac{360}{2\pi} = \frac{180}{\pi}$$
3. **Step 2: Radius and center distances**
Since $OA = OB = OC = OD = r$, the distance from center $O$ to points $A, B, C, D$ is the radius:
$$OA = OB = OC = OD = \frac{180}{\pi}$$
4. **Step 3: Angle $D\hat{O}C = A\hat{O}B$**
Because $AC = DB$ and the circles are equal and intersect symmetrically, the angle between lines $DOC$ and $AOB$ at center $O$ is the same.
The two circles intersect such that the angle between the radii to the intersection points is $60^\circ$ (since the arcs subtended by these chords are equal and the circles are equal).
Therefore,
$$D\hat{O}C = A\hat{O}B = 60^\circ$$
5. **Step 4: Length of $AB$ and $DC$**
Since $AB$ and $DC$ are chords of the circles and are equal,
Using the chord length formula:
$$\text{Chord length} = 2r \sin\left(\frac{\theta}{2}\right)$$
where $\theta$ is the central angle subtending the chord.
Here, $\theta = 60^\circ$ and $r = \frac{180}{\pi}$.
So,
$$AB = DC = 2 \times \frac{180}{\pi} \times \sin\left(\frac{60^\circ}{2}\right) = \frac{360}{\pi} \times \sin(30^\circ)$$
Since $\sin(30^\circ) = \frac{1}{2}$,
$$AB = DC = \frac{360}{\pi} \times \frac{1}{2} = \frac{180}{\pi}$$
**Final answers:**
(i) $D\hat{O}C = A\hat{O}B = 60^\circ$
(ii) $OA = OB = OC = OD = \frac{180}{\pi}$ meters
(iii) $AB = DC = \frac{180}{\pi}$ meters
Circle Angles 987472
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