They’re holiday had to be cancelled because of a fire at the hotel. is this statement correct?

No, this is not right. It should be "Their holiday had to be cancelled because of a fire at the hotel."

Explanation:

If you can change the whole sentence though, it would sound best as "Their holiday had to be cancelled due to a fire at the hotel."

Their = something they own

They're = they are

There = a place

the answer is

r ≈5.641

plug in the area of 100 yards into the equation

100=

divide each side by pi

≈ 31.8309=

take the square root of each side to find r

=r

r ≈5.641