The mean height of five students is 158cm.If another student is added to this group the mean height is then 158.4cm.What is the height of the sixth student? ​

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.