Should you keep your money in a savings account

What is the length x of the side of the triangle below? (hint: use the cosine function)

Light from the sun reaches the earth in 8.3 minutes. the velocity is 3.00 x 10^8 m/s. how far is earth from the sun? i know how to get to d = (3 x 10^8 m/s)(498 sec). i just don't know how to get from there to the answer being 1.5 x 10^11 m.

Which accounts for an increase in the temperature of a gas that is kept a constant volume