# The perimeters of the ends of the frustum of a cone are 207.24 cm and 169.56cm.if the height of the frustum be 8 cm,find the whole surface area of the

frustum. (use .3.14)

1
by ramnihal

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frustum. (use .3.14)

1
by ramnihal

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**Perimeter of 1st end = 2 π R ****
****
****⇒ 207. 24 cm = 2 x 3.14 x
R ****
****⇒**** 207.24 cm = 6.28 cm x R****
****⇒**** 33 = R****
****⇒**** i .e R = 33 ****
****
Perimeter or 2nd end = 2 π r****
****⇒**** 169. 56 cm = 2 x 3.14 x r****
****⇒**** 169. 56 cm = 6.28 cm x r****
****⇒**** 27 cm = r ****
****⇒**** i .e. , r = 27 cm****
****
So ,****
We need to find slant height first .****
****
R = 33 cm ****
r = 27 cm****
H = 8 cm ****
****
****⇒ slant height
= ****
****
****⇒ Slant height
= ****
****
****⇒ Slant height
= ****
****
****⇒ Slant height = 20 .59 ,
round it to 20.6 cm****
****
****⇒Total surface area
= π ( r + R ) l + π R² + π r ²****
****
****⇒ Total surface area =
3.14 ( 27 + 33 ) 20.6 + 3.14 ( 33)² + 3.14(27)²****
****
****⇒**** Total surface area = 3.14 ( 60 ) (20.6) + 3.14 ( 1089 ) +
3.14 ( 729)****
****
****⇒ Total Surface area = 3881.04 + 3419.46 + 2289.06**

**⇒ Total Surface area = 9589.56 cm****²**