To find the surface area of the cone-shaped spyglass, we need to calculate both the lateral surface area and the base area of the cone.
-
Lateral Surface Area (LSA):
The formula for the lateral surface area of a cone is given by:
\[ LSA = \pi r l \]
where \( r \) is the radius and \( l \) is the slant height.
Here, \( r = 6 \) cm and \( l = 18 \) cm. Thus:
\[
LSA = 3.14 \times 6 \times 18
\]
\[
LSA = 3.14 \times 108 = 339.12 \text{ square centimeters}
\]
-
Base Area (BA):
The formula for the area of the base (which is a circle) is given by:
\[ BA = \pi r^2 \]
Using \( r = 6 \) cm:
\[ BA = 3.14 \times 6^2 = 3.14 \times 36 = 113.04 \text{ square centimeters} \] -
Total Surface Area (TSA):
The total surface area of the cone is given by:
\[ TSA = LSA + BA \]
Substituting the values we calculated:
\[ TSA = 339.12 + 113.04 = 452.16 \text{ square centimeters} \]
Thus, the surface area of the spyglass is 452.16 square centimeters.