ABC26GN4957 · Volume and Surface Area
Subject: General Aptitude · Chapter: Volume and Surface Area · Exam: · Marks: · Difficulty:
The length of canvas 1.1 m wide required to build a conical tent of height 14 m and the floor area 346.5 sq. m is
(a)490 m
(b)525 m
(c)665 m
(d)860 m
Answer
Explanation
$\pi r^{2}=346.5 \Rightarrow r^{2}=\left(346.5 \times \frac{7}{22}\right)=\frac{441}{4} \Rightarrow r=\frac{21}{2}$. $$\therefore l=\sqrt{r^{2}+h^{2}}=\sqrt{\frac{441}{4}+(14)^{2}}=\sqrt{\frac{1225}{4}}=\frac{35}{2} .$$ So, area of canvas needed = $$\pi r l=\left(\frac{22}{7} \times \frac{21}{2} \times \frac{35}{2}\right) \mathrm{m}^{2}=\left(\frac{33 \times 35}{2}\right) \mathrm{m}^{2} . \text { ∴ Length of canvas }=\left(\frac{33 \times 35}{2 \times 1.1}\right) \mathrm{m}=525 \mathrm{m} .$$
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