Mensuration - III (Surface Area and Volume of a Right Circular Cylinder) — Maths STD 8 — Question
Maharashtra BoardEnglish MediumSTD 8MathsMensuration - III (Surface Area and Volume of a Right Circular Cylinder)2 Marks
Question
A rectangular strip 25cm × 7cm is rotated about the longer side. Find The total surface area of the solid thus generated.
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Answer
Since the rectangular strip of 25 cm × 7 cm is rotated about the longer side, we have:
Height, h = 25cm
Radius, r = 7cm
$\therefore$ Total surface area $=2\pi\text{r}(\text{r}+\text{h})=2\pi(7)(25+7)$
$=14\pi\ (32)$
$=448\pi\ \text{cm}^2$
$448\times\frac{22}{7}\text{cm}^2$
$=1408\text{cm}^2$
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