Question

this is very urgent Q6 I will mark you as brainliest

Answer 1

let radius be 4x cm and height be 3x cm
now the area of the base be
$\pi \times ( {4x})^{2} = 16\pi {x}^{2}$ cm²
now

$16\pi {x}^{2} = 154 \\ or. {x}^{2} = \frac{154}{16\pi} = \frac{154 \times 7}{16 \times 22} = \frac{49}{16} (as\pi = \frac{22}{7} ) \\ or. \: x = \sqrt{ \frac{49}{16} } = \frac{7}{4} \\ (side \: cannot \: be \: negative)$
now radius be
$4 \times \frac{7}{4} = 7$ cm and height be
$3 \times \frac{7}{4} = \frac{21}{4}$ cm
now the area of the curved surface be
$= \pi \times 7 \times \sqrt({ {7}^{2} } + \: ( { \frac{21}{4 } })^{2} ) \\ = \frac{22}{7} \times 7 \times \sqrt{(49 + \frac{441}{16} } ) \\ = 22 \times \sqrt{ \frac{784 + 441}{16} } \\ = 22 \times \sqrt{ \frac{1225}{16} } \\ = 22 \times \frac{35}{4} = 192.5$
cm²

Answer 2

Answer:

192.5cm²

Step-by-step explanation:

Given = r/h = 4/3

given is the are of the base , 154cm^2

pi * r² = 154

r = √154 * 7/22

r  = √49 = 7

now ,

h = 3 r / 4

h = 21 / 4

finding the slant height = l = √r² + h²

l = √49  + 441 / 16

after solving we get , l = 35 / 4

CSA of a cone is

= pi * r * L (substitute the values we get )

=22 * 7 * 35 /7 * 4

after solving answer is 192.5cm²