Again, read how the angular size of Mars is completely wrong...

http://www.freelists.org/post/geocentrism/The-resolution-of-Mars,4

Following said link I found claims that Mars is 72 million kilometers away from Earth.

In reality actual distance between Earth and Mars depends on orbital positions.

Closest is 225 million and farthes 401 million kilometers.

Using Mars' angular diameter in formulas that utilize 72 million kilometers will always give wrong result.

~~~~~

Your turn. See the calculation of the Sun's altitude.

Angular diameter of the Sun can be simply measured. You don't need distance and radius.

But you might need welder's mask.

Set point of view, set ruler at measurable distance from that point of view, read the size of the Sun at the ruler.

If D is eye to ruller distance, and d is measured Sun's appearance on the ruler,

then angular diameter is 2 * ARCTAN (d / 2D).

Since the angle is small, it can be simplified to ARCTAN (d / D).

Having welder's mask, if you want more precise measurement, you can use some stick with

known length to hold calliper at the known distance from eye (from dark glass of the mask).

When you measure it, read this, especially the second part:

https://www.theflatearthsociety.org/forum/index.php?topic=58309.90Reply #110, where you can find a way to calculate the distance of Sun from Earth's surface.