Answer:
90°
Step-by-step explanation:
EG looks like a diameter. If it is, then central angle EHD is the supplement of right angle DHG, so is 90°. The measure of arc ED is the same as the measure of its central angle, so is 90°.
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We would like to have something in the problem statement telling us that H is a point on line EG. The look of geometric figures such as this is often made to be intentionally deceiving.
