Answer:
Step-by-step explanation:
Given the information of the conical hat
=> the slant height of the hat is (use Pythagorean Theorem)
[tex]s^{2}[/tex] = [tex]r^{2} + h^{2}[/tex]
<=> [tex]s^{2}[/tex] = [tex]8^{2} + 9^{2}[/tex]
<=> s = [tex]\sqrt{145}[/tex]
The area (without the base area) of tissue paper will she need to make one hat is:
SA = πrs in2
<=> SA = π*8*[tex]\sqrt{145}[/tex] in2
<=> SA =8 [tex]\sqrt{145}[/tex] π
=> the total tissue paper will she need for 21 hats is:
SA*21
= 8 [tex]\sqrt{145}[/tex] π*21
= 6352,18 in 2