Question

Mayank made a nice bird-bath for his garden in the shape of a cylinder with a hemispherical depresstion at one end. The height of the cylinder is 1.45m and its radius is 30cm. Find the total surface area of the bird bath.​

Answer 1

$\huge\star{\underline{\mathbb{\red{A}\pink{n}\green{s}\blue{w}\purple{e}\orange{r}}}}$

$\longrightarrow$$\sf\pink{TSA\:=\:CSA\:of\:cylinder\:+\:CSA\:of\:hemisphere}$

$\longrightarrow$$\sf\blue{2πrh\:+\:{2\pi \: r}^{2}\:=\:2πr(h+r)}$

$\longrightarrow$$\sf\green{2 \times \frac{22}{7} \times 30(145 + 30) {cm}^{2}}$

$\longrightarrow$$\sf\purple{{33000cm}^{2}}$

$\longrightarrow$$\sf\red{{3.3cm}^{2}}$

${\huge{\underline{\small{\mathbb{\blue{HOPE\:HELP\:U\:BUDDY :)}}}}}}$

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Answer 2

$\longrightarrow$Let h be the height of the cylinder and r be the common radius of the cylinder and hemisphere.

➠ Then, the total surface area of the bird-bath = CSA of cylinder + CSA of the hemisphere

= 2πrh + 2πr2

= 2π r(h + r)

= 2 (22/7) × 30 × (145 + 30) cm2

= 33000 cm2 = 3.3 m2

hence, area of bird bath is 3.3 m2