15/79 is already in simplest form. So, as a decimal it would be 0.215189873. It is hard to do long division on here so I won’t be able to show works
Peter spent $34.22
2.76(12.4)=34.224
We can determine that the ratio is simplified by checking that the numbers in ratio can be divided with the same number, if it can be divided then it is not simplified for example 9:12 is the ratio and we can divide both numbers with 3 and then we get 3 : 4.
Now we cannot divide 3:4 further with any same number so this is simplified form.
The formula for the period T of a pendulum is T = 2π Square root of√L/g, where L is the length of the pendulum and g is the acceleration due to gravity.
