Question

in a building there are 4cylinder pillars. the radius of each pillar is 35cm and height is 4m. find the total curved surface area of the pillars.​

Answer 1

GIVEN :-

• There are 4 cylindrical pillars.
• Radius of each pillar is 35cm and height is 4m.

TO FIND :-

• Curved Surface Area(C.S.A) of all the pillars.

TO KNOW :-

$\\ \bigstar\boxed{ \sf \: C.S.A \: of \: cylinder = 2\pi \: rh}$

Here ,

• r is radius of Cylinder.
• h is height of Cylinder.
• π = 22/7

★ 100cm = 1m

★ 1000cm² = 1m²

SOLUTION :-

We have ,

• Height = 4m = 400cm
• Radius = 35cm

Putting values in formula ,

$\\ \sf \: C.S.A \: of \: cylinder = 2\pi \: rh \\ \\ \sf \: C.S.A \: of \: cylinder = 2 \times \frac{22}{ \cancel7} \times \cancel {35} \: \: ^{5} \times 400 \\ \\ \sf \: C.S.A \: of \: cylinder = 2 \times 22 \times 5 \times 400 \\ \\ \sf \: C.S.A \: of \: cylinder = 88000 {cm}^{2}$

Area of one cylinder is 88000cm².

♦ C.S.A of 4 Cylinder = 4 × Area of One cylinder

→ C.S.A of 4 Cylinder = 4 × 88000

→ C.S.A of 4 Cylinder = 352000cm²

Hence , area of 4 Cylinder is 352000cm² or 352m².

MORE TO KNOW :-

★ T.S.A of Cylinder = 2πr(r+h)

★ C.S.A. of Cube = 4edge²

★ T.S.A. of Cube = 6edge²

★ C.S.A of Cuboid = 2(lh+bh)

★ T.S.A of Cuboid = 2(lh + bh + lb)

★ C.S.A of Cone = 2πrl

★ T.S.A of Cone = 2πr(r+l)

★ T.S.A of Sphere = 4πr²

★ T.S.A of Semi-circle = 3πr²

Answer 2

$\large\underline\blue{\bold{Given \:  Question :-}}$

• In a building, there are 4 cylinder pillars. The radius of each pillar is 35 cm and height is 4 m. Find the total curved surface area of the pillars.

$\large\underline\purple{\bold{Solution :- }}$

$\begin{gathered}\begin{gathered}\bf \:Given - \begin{cases} &\sf{radius \: of \: cylindrical \: pillar \: (r) = 35 \: cm} \\ &\sf{height \: of \: pillar \: (h) = 4 \: m = 400 \: cm} \end{cases}\end{gathered}\end{gathered}$

$\begin{gathered}\begin{gathered}\bf \: To\: find - \begin{cases} &\sf{surface \: area \: of \: 4 \: cylinders}  \end{cases}\end{gathered}\end{gathered}$

$\begin{gathered}\Large{\bold{\blue{\underline{Formula \: Used \::}}}} \end{gathered}$

$\:\:\boxed{ \green{ \bf \:Curved \: Surface \: Area_{(cylinder)} =2\pi \: rh }}$

Now,

It is given that

• Radius of cylindrical pillar, r = 35 cm

• Height of cylindrical pillar, h = 400 cm

So,

• Total Surface area of 1 pillar = Curved Surface area

$\rm :\implies\:CS A_{(cylinder)} =2\pi \: rh$

$\rm :\implies\:CS A_{(cylinder)} = 2 \times \dfrac{22}{7} \times 35 \times 400$

$\rm :\implies\:CS A_{(cylinder)} = 88000 \: {cm}^{2}$

So,

$\tt \: Total \: surface \: area \: of \: 4 \: pillars = 4 \times \:CS A_{(cylinder)}$

$\tt \: Total \: surface \: area \: of \: 4 \: pillars = 4 \times 88000$

$\tt \: Total \: surface \: area \: of \: 4 \: pillars = 352000 \: {cm}^{2}$

More information :-

Perimeter of rectangle = 2(length× breadth)

Diagonal of rectangle = √(length ²+breadth²)

Area of square = side²

Perimeter of square = 4× side

Volume of cylinder = πr²h

T.S.A of cylinder = 2πrh + 2πr²

Volume of cone = ⅓ πr²h

C.S.A of cone = πrl

T.S.A of cone = πrl + πr²

Volume of cuboid = l × b × h

C.S.A of cuboid = 2(l + b)h

T.S.A of cuboid = 2(lb + bh + lh)

C.S.A of cube = 4a²

T.S.A of cube = 6a²

Volume of cube = a³

Volume of sphere = 4/3πr³

Surface area of sphere = 4πr²

Volume of hemisphere = ⅔ πr³

C.S.A of hemisphere = 2πr²

T.S.A of hemisphere = 3πr²