The formula to calculate the surface area of a cone is SA = πr(r + √(r^2 + h^2)), where r is the radius and h is the height.
Given that the radius is 9 and the height is 21, we can plug these values into the formula:
SA = π(9)(9 + √(9^2 + 21^2))
SA = π(9)(9 + √(81 + 441))
SA = π(9)(9 + √(522))
SA = π(9)(9 + 22.85)
SA = π(9)(31.85)
SA = 285.6π
Now, we can calculate the surface area:
SA ≈ 285.6 * 3.14
SA ≈ 897.84 cm2
Rounded to the nearest tenth, the surface area of the cone is 897.8 cm2.
Therefore, the closest answer is 848.2 cm2.
What is the surface area of the cone to the nearest tenth? The figure is not drawn to scale.
radius of 9
height of 21
cone
(1 point)
Responses
207.0 cm2
207.0 cm 2
1,442.0 cm2
1,442.0 cm 2
848.2 cm2
848.2 cm 2
229.5 cm2
1 answer