The problem asks us to identify which of the given arcs represents a semicircle based on the provided diagram of a circle. A semicircle is an arc that measures 180 degrees, meaning the endpoints of the arc are diametrically opposite, i.e., they form a diameter.

GeometryCircleArcSemicircleDiameterAngle Measurement
2025/3/28

1. Problem Description

The problem asks us to identify which of the given arcs represents a semicircle based on the provided diagram of a circle. A semicircle is an arc that measures 180 degrees, meaning the endpoints of the arc are diametrically opposite, i.e., they form a diameter.

2. Solution Steps

Let's analyze each option:
* Arc BCE: We are given that angle BHC=76BHC = 76^{\circ}. Since BHCBHC is a central angle, the measure of arc BCBC is also 7676^{\circ}. A semicircle has a measure of 180180^{\circ}. So we need to determine if arc CECE has a measure of 18076=104180^{\circ} - 76^{\circ} = 104^{\circ}. We don't have enough information to determine if the arc is actually 104 degrees. However, since AA appears to be the top of the circle, ACAC could represent something close to a diameter. BB and EE would not be opposite.
* Arc CEA: The straight line passing through point AA is a tangent. Therefore, AA is the top most point. Also ACAC looks like it might be a diameter. If ACAC is a diameter, the arc CACA would be equal to 180 degrees. Since CEACEA looks like a reasonable diameter, let us assume ACAC passes through point HH. Then CEACEA is a reasonable choice.
* Arc GBC: We know arc BCBC measures 7676^{\circ}. We don't have enough information to determine if the remaining arc GBGB would give a sum of 180 degrees. But just by inspection, GBGB is much less than 180-76 =
1
0
4.
* Arc FCB: We know arc BCBC measures 7676^{\circ}. We don't have enough information to determine if the remaining arc FBFB would give a sum of 180 degrees. But just by inspection, FCFC is much greater than
1
0
4.
Based on the diagram, it appears that ACAC is a diameter, therefore CEACEA is an approximate semicircle.

3. Final Answer

CEA

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