Make a sketch, (it won't be to scale!)
You will have an isosceles triangle with an angle at the earth of 31 minutes of angle.
Draw in a perpendicular which would be
360,000 km
If the radius of the moon is r, I see it as
tan (0°15'30") = r/360000
r = 360000(tan(0°15'30") ) = 1623 km
= appr 1600 km
Google states the radius as 1737 km
PS,
on my calculator I have a key labeled
D°M'S" which I used for my angle above,
you could also have
31 minutes = 31/60 °
then half would be 31/120°
The moon's distance from the earth is 360000 km and its diameter subtends an angle of 31 minute at the of the observer on the earth . Find the radius of the moon.
1 answer