the total surface area of right circular cone is90πcm^2 . it's slant height is 13cm .find its radius . please answer question please please please please
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Heya!!
TSA of cone = 90*pi cm^2
Slant height = 13 cm
To find radius:
Since,
TSA of cone = pi*r (l+r)
=) 90*pi = pi *r (13+r)
=) 90 = r (13+r)
=) 90 = 13r + r^2
=) r^2 + 13r - 90 = 0
=) r^2 + 18r - 5r - 90 = 0
=) r (r + 18) - 5 (r + 18) = 0
=) (r+18) (r - 5) = 0
=) r = 5
Hence, the radius should be 5 cm.
Hope it helps u.
TSA of cone = 90*pi cm^2
Slant height = 13 cm
To find radius:
Since,
TSA of cone = pi*r (l+r)
=) 90*pi = pi *r (13+r)
=) 90 = r (13+r)
=) 90 = 13r + r^2
=) r^2 + 13r - 90 = 0
=) r^2 + 18r - 5r - 90 = 0
=) r (r + 18) - 5 (r + 18) = 0
=) (r+18) (r - 5) = 0
=) r = 5
Hence, the radius should be 5 cm.
Hope it helps u.
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hope this helps u.....there are two radii
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