Assuming that Anita needs hollow right circular cones, we are solving for its lateral surface area, which is given by the formula πr√ (h²+r²), where r is the radius and h is the height.
r = 6 ft / 2 = 3 ft
Solving for the lateral surface area of one cone:
LSA = (3.14) (3) [√ (12²+3²) ] = 116.52 sq ft.
Since she needs 10 cones:
10 * 116.52 sq. ft = 1,165.2 sq ft.
She will need 1,165.2 sq ft of material.
Hope this helps you :)