Our sun orbits around the center of our galaxy (the Milky Way) once every 2.5 x 108 years. The radius of the sun's orbit about the center of the galaxy is approximately 3.15 x 1020 m. The sun has made only about 20 revolutions since the Earth was formed over 3 billion years ago! The centripetal force keeping our sun in orbit is supplied by the force of gravity. Calculate the mass of the galaxy.
(ans. 2.98 x 1041 kg)
Can someone help me reach the answer