The surface area of the cone would be 216. 66 cm².
If the diameter and the slant height of a cone are cut in half, the area would become 1 / 4 of the original area.
How to find the are ?
The area of a cone is:
SA = πr ( r + l )
= 3.14 x 3 x (3 + 20)
= 3.14 x 3 x 23
= 216. 66 cm²
If the slant height and diameter are cut in half :
Diameter new = 6 / 2
= 3 cm
Slant height :
= 20 / 2
= 10 cm
The new area of the cone is:
= 3. 14 x 1. 5 x (1.5 + 10)
= 3.14 x 1. 5 x 11. 5
= 54. 165 cm²
Compared to the old are:
= 54. 165 / 216. 66
= 1 / 4
When you halve the dimensions, the surface area becomes one-fourth of the original.
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