Hello ….…

Can you explain this with steps ..

How will you weigh the sun , that is estimate its mass ? The mean orbital radius of the earth around the sun is 1.5 x 10^8 km .

@ jeeva 
orbital radius is given , 
so, time taken by the earth to complete one revolution 
T = 1 year = 365 . 25 days . 
= 365.25 * 24 * 60 * 60 
universal gravitational constant = 6.67 * 10 ^ -11 
so, mass of sun can be calculated using the relation 
M = 4 pie square r cube / G T square 
by plugging in the value answer will be 2.0 * 10 ^ 30 kg , 
hope it clears now