Question

what is the answer of these ouestion ???

Answer 1

theta (in radians) = Arc/radius.

Here, D (distance from the planet to the earth) can be treated as the radius, and the Diameter of the planet can be treated as an Arc with earth as the centre of the circular path (orbit) it traces
And since the arc at such a large radius is almost like a straight line as seen from the observatory on Earth,

Theta = Diameter of the planet/ D

Therefore,

Diameter of the planet = D.Theta