Question

Question in attachment.​

Answer 1

$\sf\small{ \underline{\underline{ \pmb{Given:-}}}}$

• h = 77 cm
• d = 4 cm
• r = 4/2= 2 cm
• D = 4.4 cm
• r = 4.4/2 = 2.2 cm

$\sf\small{ \underline{\underline{ \pmb{To \: Find:-}}}}$

• inner curved surface area
• Outer curved surface area
• total surface area

$\sf\small{ \underline{\underline{ \pmb{Formula:-}}}}$

★ Formula that we use

• $\boxed{ \red{ \sf \: curved \: surface \: area = 2\pi rh}}$
• $\boxed{ \red{ \sf \: Total \: surface \: area = 2(BA) + CSA(r) + CSA(R)}}$

$\sf\small{ \underline{\underline{ \pmb{Solution:-}}}}$

$\sf \: ➊ \: Curved \: surface \: area = 2πrh$

$\sf \implies 2 \times \frac{22}{7} \times 2 \times 77$

$\sf \implies 88 \times 11$

$\sf \implies 968 \: {cm}^{2}$

$\sf$

$\sf \: ➋ \: Curved \: surface \: area=2πRh$

$\sf \implies 2 \times \frac{22}{7} \times 2.2 \times 77$

$\sf \implies 44 \times 2.2 \times 11$

$\sf \implies 484 \times 2.2$

$\sf \implies 1064.8 \: {cm}^{2}$

$\sf$

$➌\sf \: Total \: surface \: area = 2(BA) + CSA(r) + CSA(R)$

$\sf \implies 2\pi (R²-r²) + 968 + 1064.8$

$\sf \implies 2 \times \frac{22}{7}( {2.2}^{2} - {2}^{2} ) + 2032.8$

$\sf \implies \frac{44}{7} \times (4.84 - 4) + 2032.8$

$\sf \implies \frac{44}{7} \times 0.84 + 2032.8$

$\sf \implies 5.28 + 2032.8$

$\sf \implies \red{2036.08 \: {cm}^{2} }$