ABC26GN4952 · Volume and Surface Area
Subject: General Aptitude · Chapter: Volume and Surface Area · Exam: · Marks: · Difficulty:
If the area of the base of a right circular cone is 3850 $\mathrm{cm}^{2}$ and its height is 84 cm, then the curved surface area of the cone is
(a)$10001 \mathrm{cm}^{2}$
(b)$10010 \mathrm{cm}^{2}$
(c)$10100 \mathrm{cm}^{2}$
(d)$11000 \mathrm{cm}^{2}$
Answer
Explanation
$\pi r^{2}=3850 \Rightarrow r^{2}=\left(\frac{3850 \times 7}{22}\right)=1225 \Rightarrow r=35$. Now, $r=35 \mathrm{cm}, h=84 \mathrm{cm}$. $$\text { So, } l=\sqrt{(35)^{2}+(84)^{2}}=\sqrt{1225+7056}=\sqrt{8281}=91 \mathrm{cm} \text {. } \text { ∴ } \text { Curved surface area }=\left(\frac{22}{7} \times 35 \times 91\right) \mathrm{cm}^{2}=10010 \mathrm{cm}^{2} .$$
Open in whiteboard · Browse this chapter in the app