The Gateway Arch in St. Louis, MO is approximately 630 ft tall. How many U. S. half dollars would be in a stack of the same height? Each half dollar is 2.15 mm thick.

The number of half dollars in the stack of the height of the Gateway Arch in St. Louis is 89,313 half dollars

Explanation:

The given height of the Gateway Arch in St. Louis = 630 ft

The thickness of each half dollar = 2.15 mm

By conversion of factors, we have;

1 feet = 304.8 mm

Therefore;

630 ft. = 304.8 × 630 mm = 192,024 mm

The number of half dollars that will stack up to 630 ft or 192,024 mm, is therefore, given as follows;

The number, n, of half dollars in the stack of the height of the Gateway Arch in St. Louis = The height of the Gateway Arch in St. Louis/(The thickness of each half dollar)

n = 630 ft/(2.15 mm/(half dollar)) = 192,024 mm/(2.15 mm/(half dollar)) = 89,313.49 ≈ 89,313 half dollars

The number of half dollars in the stack of the height of the Gateway Arch in St. Louis = 89,313 half dollars.

i'm assuming that the correct answer is indeed the first one/ "a"..