Math, asked by UVESHGOUR, 1 year ago

The radius and height of a cone are in the ratio 4:3 the area of the base is 154 cm square find the are of curd surface

Answers

Answered by komalchauhan1
28
HEY DEAR.....!!!

We have given the ratio of radius and height i.e 4 : 3

Let 

Radius = 4x

Height = 3x

Slant Height = root [(4x)2 +(3x)2 ]=5x {Pythagoreus Theorem}

 We know that 

Area of Base = pie X radius2 

154=22/7 X 16x2

--->x=1.75cm

Radius=7

Height =5.25cm

Slant Height =8.75cm 

Curved Surface Area = pie X radius x slant height
=22/7 X 7 X 8.75

-->x=192.5cm2

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HOPE IT'S HELP U....!!! ☺
Answered by Anonymous
7

★ Question ★

\rule{300}2

the radius and height of a cone are in ratio 4:3 . the area of the base is 154cm^{2}. find the area of curved surface.

\rule{300}2

◇ Answer ◇

radius and height =.4:3

let the unit of ratio be = x

then,

r=4x

h=3x

slant height ( length) =↓

\implies L^{2}=r^{2}+h^{2} \\ \implies l^{2}=4^{2}+3^{2} \\ \implies l^{2}=16+9 \\ \implies l^{2}=25 \\ \implies l=\sqrt25 \\ \implies = l=5

★ Area of the base = πr^{2}

\implies 154= \frac{22}{7}×4x^{2}

 \implies 4x^{2}=\frac{154×7}{22}

\implies 4x^{2}=7×7

 \implies x^{2}=\frac{7×7}{16}

 \implies x^{2}=\sqrt\frac{7×7}{4×4}

\implies x=\frac{7}{4}

\implies radius = \frac{7}{4}×4

\implies radius = 7cm

Now,

slant height ↓

\implies \frac{5×7}{4} \\ \implies \frac{35}{4} cm

→ C.S.A = πrl

 \implies \frac{22}{7}×7×\frac{35}{4} \\ \implies \frac{776}{4} \\ \implies 192.5cm^{2}

\rule{300}2

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