To find the slant height of the cone, we can use the Pythagorean theorem. First, we need to determine the radius of the cone since the diameter is given.
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Calculate the radius:
Given the diameter is 13 cm, the radius \( r \) is:
\[ r = \frac{d}{2} = \frac{13 , \text{cm}}{2} = 6.5 , \text{cm} \] -
Use the Pythagorean theorem:
In a right triangle formed by the height, the radius, and the slant height, we have: \[ l^2 = h^2 + r^2 \] Where:- \( l \) is the slant height
- \( h = 6 , \text{cm} \) (height of the cone)
- \( r = 6.5 , \text{cm} \) (radius of the cone)
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Plug the values into the equation:
\[ l^2 = 6^2 + (6.5)^2 \] \[ l^2 = 36 + 42.25 \] \[ l^2 = 78.25 \] -
Calculate the slant height \( l \):
\[ l = \sqrt{78.25} \approx 8.83 \] -
Round to the nearest tenth:
\[ l \approx 8.8 , \text{cm} \]
So, the slant height must be approximately 8.8 cm.