Find the surface area of a cone with a radius of 4 cm and a slant height of 5 cm

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Question: Find the surface area of a cone with a radius of 4 cm and a slant height of 5 cm.

Options:

Correct Answer: 50.24 cm²

Solution:

Surface Area = πr(l + r) = π(4)(5 + 4) = π(4)(9) = 36π ≈ 113.10 cm²

Find the surface area of a cone with a radius of 4 cm and a slant height of 5 cm.

Find the surface area of a cone with a radius of 4 cm and a slant height of 5 cm.

Step 1: Identify the formula for the surface area of a cone, which is Surface Area = πr(l + r).
Step 2: Identify the values given: radius (r) = 4 cm and slant height (l) = 5 cm.
Step 3: Substitute the values into the formula: Surface Area = π(4)(5 + 4).
Step 4: Calculate the expression inside the parentheses: 5 + 4 = 9.
Step 5: Now substitute this back into the formula: Surface Area = π(4)(9).
Step 6: Multiply 4 and 9: 4 * 9 = 36.
Step 7: So, the surface area is Surface Area = 36π.
Step 8: If needed, calculate the approximate value: 36π ≈ 113.10 cm².

Surface Area of a Cone – The formula for the surface area of a cone is given by SA = πr(l + r), where r is the radius and l is the slant height.