I need some help. I have tried working this problem and can't get it.
What is the mass of the Sun, in kilograms, based on the revolution period and distance from Venus?
You can use Newton's form of Kepler's third law to compute the mass of the sun, using the distance and period of any planet. You can find the formula at:
http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970609f.html
The formula given there uses the velocity of the planet (in m/s), which is the orbit circumference divided by the period.
You should get Msun = abiout 2*10^30 kg