Find the geometric mean of $45$45 and $5$5. Give your answer in exact form.

Find the geometric mean of $19$19 and $13$13. Give your answer to two decimal places.

Find the side length of a square with the same area as a rectangle with length $100$100 m and width $4$4 m.

Find the side length of a square with the same area as a rectangle with length $29$29 mm and width $11$11 mm. Give you answer to three decimal places.