Question

An umbrella you bought is shaped like a regular octagonal pyramid with a side length of four feet and a slant height of five feet. Estimate the amount of fabric that the umbrella has.

Answer 1

1/2 the 5 times 4= 110.0 which should be answer:)

Answer 2

we know that
[amount of fabric]=8*[area of lateral triangle side]
area of lateral triangle side=(1/2)*4*5----> 10 ft²
so
[amount of fabric]=8*[10]----> 80 ft²

the answer is
80 ft²