As shown in the above diagram, a person starts from the centre O of a circular path AB, walks along the line indicated by arrows and returns to the same point. If the radius OA = OB = 100 metres, what is the total distance walked to the nearest metres?
A common interpretation of such a diagram involves the person walking from the center to a point on the circumference, along an arc of the circle, from the end of the arc back to the center. Given points A and B are mentioned, a likely path is O -> A -> Arc AB -> B -> O.
The total distance walked would be the sum of the lengths of the segments OA, Arc AB, and BO.
Distance OA = radius = 100 m.
Distance BO = radius = 100 m.
Distance = 100 + Length of Arc AB + 100 = 200 + Length of Arc AB.
The length of an arc AB is given by $L = r \times \theta$, where $r$ is the radius and $\theta$ is the central angle AOB in radians. We need to determine the angle AOB from the context or options.
The options for total distance are 703, 723, 743, 823 m.
This implies the length of Arc AB is approximately:
703 – 200 = 503 m
723 – 200 = 523 m
743 – 200 = 543 m
823 – 200 = 623 m
Let’s check if any common central angle results in an arc length close to these values when the radius is 100m.
If the central angle is $\theta$ radians, Arc length = $100\theta$.
If $\theta = 503/100 = 5.03$ rad $\approx 288$ deg.
If $\theta = 523/100 = 5.23$ rad $\approx 300$ deg (using $\pi \approx 3.1416$, $5.23 \times 180/\pi \approx 299.57$ deg).
If $\theta = 543/100 = 5.43$ rad $\approx 311$ deg.
If $\theta = 623/100 = 6.23$ rad $\approx 357$ deg.
A central angle of 300 degrees is a plausible value in geometry problems (e.g., a circle minus a 60-degree sector).
If the central angle AOB is 300 degrees, which is $300 \times \frac{\pi}{180} = \frac{5\pi}{3}$ radians.
Arc length AB = $100 \times \frac{5\pi}{3} = \frac{500\pi}{3}$ metres.
Using $\pi \approx 3.14159$: Arc length $\approx \frac{500 \times 3.14159}{3} \approx \frac{1570.795}{3} \approx 523.598$ metres.
Total distance = $100 + 523.598 + 100 = 723.598$ metres.
Rounded to the nearest metre, this is 724 m.
Let’s try a different approximation for $\pi$, like $\pi \approx 22/7$.
Arc length $\approx \frac{500}{3} \times \frac{22}{7} = \frac{11000}{21} \approx 523.81$ metres.
Total distance = $100 + 523.81 + 100 = 723.81$ metres. Rounded to 724m.
If the arc length was exactly 523m, the total distance would be 723m. This matches Option B. The angle corresponding to an arc length of 523m with radius 100m is 5.23 radians (approx 299.57 degrees).
Given the options, it is highly probable that the intended path is O -> A -> Arc AB -> B -> O and the arc length AB is precisely 523m, leading to a total distance of 723m. This would mean the angle AOB is $5.23$ radians, or the question expects calculation precision that rounds $723.something$ down to 723. Assuming the intended total distance is exactly 723 based on the options, the arc length is 523.