The surface area of a cone is given by the following formula:
[tex]SA=\pi rs+\pi r^2[/tex]
Where SA is the surface area, s is the slant and r is the radius. Replace for the given values:
[tex]\begin{gathered} SA=(3.14)\cdot(2.7)\cdot(8.6)+(3.14)\cdot(2.7)^2 \\ SA=72.91+22.89 \\ SA=95.8 \end{gathered}[/tex]
Each ornament has 2 cones, it means that each ornament has a surface area of:
[tex]SA=2\cdot95.8=191.6[/tex]
If she needs to paint 70 ornaments, she will have to paint:
[tex]SA=191.6\cdot70=13412[/tex]
According to the question statement, she uses one bottle of paint to paint 202cm^2. To find how many bottles she needs to paint 70 ornaments, divide the total area of the 70 ornaments by 202:
[tex]\frac{13412}{202}=66.39[/tex]
The answers are:
1. The surface area of one ornament is about 191.6 cm^2.
2. She needs 67 bottles.
