To find the physical diameter of the Sun, we can use the formula for angular size:
d = D * tan(Θ/2),
where d is the physical diameter, D is the distance from the observer to the object, and Θ is the angular size.
Given that the angular diameter of the Sun is about 0.5 degrees and its average distance is about 150 million km, we have:
d = 150 million km * tan(0.5∘/2) = 150 million km * tan(0.25∘)
Since the tangent function is a continuous function, we can use an approximation to find its value:
tan(0.25∘) ≈ 0.0043
Therefore:
d ≈ 150 million km * 0.0043 = 645,000 km
So, the Sun's approximate physical diameter is 645,000 km