Identify the radius of the following cone.

A cone is marked with a height of 12 centimeters and a radius of 5 centimeters, both shown as perpendicular dotted lines.
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1 answer

To identify the radius of the cone as given in the problem, we start by noting that the radius is already provided: 5 centimeters. However, if needed, let’s clarify how these measurements relate to the cone's geometry.

Given:

  • Height (h) of the cone = 12 cm
  • Radius (r) of the cone = 5 cm

Formulae:

  1. Volume of a Cone: \( V = \frac{1}{3} \pi r^2 h \)
  2. Surface Area of the Cone:
    • Lateral Area: \( A_L = \pi r l \) (where \( l \) is the slant height)
    • Base Area: \( A_B = \pi r^2 \)
    • Total Surface Area: \( A = A_L + A_B = \pi r l + \pi r^2 \)

Slant Height Calculation:

The slant height \( l \) of a cone can be found using the Pythagorean theorem, considering the radius and height as the two shorter sides of a right triangle, with the slant height being the hypotenuse:

\[ l = \sqrt{r^2 + h^2} \]

Substituting the values we have:

\[ l = \sqrt{5^2 + 12^2} = \sqrt{25 + 144} = \sqrt{169} = 13 \text{ cm} \]

Summary:

  • The radius of the cone is already provided as 5 centimeters.
  • The calculated slant height is 13 centimeters.

If you need any further information or other specific calculations related to the cone, please let me know!