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2014-08-15T01:55:56+05:30

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Lateral surface area is given by π R L    L = lateral length or lateral height
L² = R² + H²            H = height of cone
L²   =  R² + 2.8²    ----- equation 1

23.10 = 3.14 * R * L
R L = 7.353  cm²
L  = 7.353 / R

Substitute in equation 1

7.353² /R² = R² + 2.8²

R^4 + 7.84 R² - 54.066  = 0

Δ =  277.73
R²  =  4.412

R = 2.1  cm
L = 3.5 cm


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2014-08-15T17:02:15+05:30

This Is a Certified Answer

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Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
Lateral surface area is given by πrl    l = lateral height
l² = r² + h²            h = height of cone = 2.8 cm
l = √ (r² + 2.8²)    -----  i

23.10 = 3.14 × r × l
rl = 7.353  cm²
l  = 7.353 / r

So

7.353/r = √(r² + 2.8²)
7.353² /r² = r² + 2.8²  

r + 7.84r² - 54.066  = 0 

solving r

r = 2.1003 cm

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