Question

Find the total surface area of a hollow
cylindrical pipe of length 50 cm, external
diameter 12 cm and internal diameter 9 cm.-

Answer 1

Answer:

given,length of the pipe/hallow cylinder =50cm

external diameter=12cm(d=r/2)

external radius =6cm=r1

internal diameter=9cm(d=r/2)

internal radius=4.5=r2

Total surface area of a hallow cylinder =2pie(r1+r2)(r2-r1+h)

=2×22/7(6+4.5)(4.5-6+50)

SOLVE IT THEN YOU'LL GET THE REQUIRED ANSWER

Answer 2

$\huge \: answer$

The internal radius=12÷2=6cm

The external radius =9÷2=4.5cm

CSA of the pipe,

$\longrightarrow \: 2\pi h \: (r + r)$

•h=length

•R=External radius

•r=internal radius

$\longrightarrow \: 2 \times \frac{22}{7} \times 50(6 + 4.5) \\ \longrightarrow \: 2 \times \frac{22}{7} \times 50 \times 10.5 \\ \longrightarrow \: \frac{23100}{7}$

CSA=3300cm²

Area of two circular sides,

$\longrightarrow2 \times \frac{22}{7} ( {6}^{2} - {4.5}^{2} ) \\ \longrightarrow \: 2 \times \frac{22}{7} \times 15.75 \\ \longrightarrow \: 99 {cm}^{2}$

Now ,the two surface area

$(3300 + 99) {cm}^{2}$

TSA=3399cm²

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