How do you find the diameter of the sun, given angular diameter and distance?

Angular diameter is 1/2 degree
and distance is 1.5 X 10^8 km

1 Answer
A. S. Adikesavan
Feb 14, 2016

The angular diameter of the Sun is nearly 0.5334 deg. The diameter of the solar disc is nearly (Earth-Sun distance) X (angular diameter in radian) = 149598262 X (0.5334 #pi# /180) = 1392700 km..

Explanation:

When the radius of a circle is large and the angle subtended by an arc is small, the arc will be nearly straight. So, the arc length is nearly the chord length. Arc length = (radius) X (angular spacing in radian). A better approximation is from 2 X distance X sin (angular spacing / 2). sin x is nearly x, when x is very small. This formula also gives the same 5-sd value.1.3927 E+05 km. Increasing precision in angular spacing, we get more sd in the answer.

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