To calculate the surface area of a cone, we use the formula:
\[ \text{Surface Area} = \pi r (r + l) \]
where:
- \( r \) is the radius,
- \( l \) is the slant height,
- \( \pi \) is approximately 3.14.
1. Surface Area of the Cone (slant height = 8 meters, radius = 5 meters)
Using the formula:
\[ \text{Surface Area} = \pi r (r + l) = 3.14 \times 5 \times (5 + 8) = 3.14 \times 5 \times 13 = 3.14 \times 65 = 204.1 \text{ square meters} \]
Answer: 204.1 square meters
2. Surface Area of the Cone (diameter = 12 feet, slant height = 14 feet)
First, find the radius:
\[ r = \frac{12}{2} = 6 \text{ feet} \]
Now, using the formula:
\[ \text{Surface Area} = \pi r (r + l) = 3.14 \times 6 \times (6 + 14) = 3.14 \times 6 \times 20 = 3.14 \times 120 = 376.8 \text{ square feet} \]
Now convert square feet to square centimeters (1 square foot = 929.0304 square centimeters):
\[ 376.8 \text{ square feet} \times 929.0304 = 350,148.883 \text{ square centimeters} \]
Answer: 350,148.9 square centimeters
3. Surface Area of the Cone (height = 11, radius = 6)
First, we need to calculate the slant height \( l \) using the Pythagorean theorem:
\[ l = \sqrt{h^2 + r^2} = \sqrt{11^2 + 6^2} = \sqrt{121 + 36} = \sqrt{157} \approx 12.53 \text{ (approx)} \]
Now, find the surface area:
\[ \text{Surface Area} = \pi r (r + l) = 3.14 \times 6 \times (6 + 12.53) = 3.14 \times 6 \times 18.53 \approx 3.14 \times 111.18 \approx 349.50 \]
Answer: 349.5 square units
4. Surface Area of the Funnel (diameter = 6 inches, slant height = 4 inches)
First, find the radius:
\[ r = \frac{6}{2} = 3 \text{ inches} \]
Using the surface area formula:
\[ \text{Surface Area} = \pi r (r + l) = 3.14 \times 3 \times (3 + 4) = 3.14 \times 3 \times 7 = 3.14 \times 21 = 65.94 \text{ square inches} \]
Answer: 65.94 square inches
5. Surface Area of the Waffle Cone (slant height = 8 inches, radius = 3 inches)
Using the formula:
\[ \text{Surface Area} = \pi r (r + l) = 3.14 \times 3 \times (3 + 8) = 3.14 \times 3 \times 11 = 3.14 \times 33 = 103.62 \text{ square inches} \]
Answer: 103.62 square inches