Surface Area of a Cone

Find the surface area of a cone with radius $3$ and height $4$. Use π ≈ $3.14$.

• 1Find the slant height: l = √($3^2+4^2$) = √($9+16$) = √$25=5$
• 2Base area: $3.14\times 9=28.26$
• 3Curved surface: $3.14\times 3\times 5=47.1$
• 4Add: $28.26+47.1$

Answer: $75.36$

Find the surface area of a cone with radius $6$ and height $8$. Use π ≈ $3.14$.

• 1Slant height: l = √($36+64$) = √$100=10$
• 2Base area: $3.14\times 36=113.04$
• 3Curved surface: $3.14\times 6\times 10=188.4$
• 4Add: $113.04+188.4$

Answer: $301.44$