The tree was approximately 40.8ft tall.
You use the equation, a^2+b^2=c^2.
12^2 + 39^2 = x^2, add the results of 12^2 and 39^2 to make 1665 = x^2. You can take the positive root of both sides, 3√185, and it equals 40.80441152, which is rounded to 40.8.
Astronomers deal with objects in space, so it's most likely they would use geometry to determine how far they are, how big they are, etc.
Have a nice day! :)
1
Mark brainliest please
Hope this helps you
