"Georgivs Sextvs Rex" is latin for "King George the Sixth". King George VI was King of Great Britain from 1936 to 1952. If the coin says only "Georgivs Sextvs Rex" on the obverse, it is likely not from Britain but rather one of its colonial holdings - the name of the colony would be on the coin somewhere. British Coins from the reign of George VI usually have a somewhat longer phrase of abbreviated latin which translates to "George the Sixth, by the Grace of God, King of all Britons, Defender of the Faith [and until 1947] and Emperor of India." Most (although not all) coins bearing a portrait of George VI show him facing to the left and without a crown.
ALL British coins have that inscription so it really doesn't help to ID a coin. Please look for the coin's denomination and post a new question. Old British coins have strange values so you may see words like shilling, florin, farthing, etc.
That depends on which coin, from where.
Can you be more specific? What denomination coin?
the coin has the president on it
A semicircle.
Yes.
100
It doesn't look like anything because there's no such thing.
it looks like a silver coin with 100 on it
It looks like the back of the coin, with a real big eagle.
Look at the coin again. The first US one cent coin was struck in 1793.
It has a woman on the front, and trees on a beach on the back. It is a very lovely coin.