Discussion
A boy cut a sector containing an angle of 140° from a circle of radius 15 cm and he folded the sector into a cone. What is the curved surface area of the cone \(\left(\pi = \frac{22}{7}\right)\).
Answer: C
The curved surface area is 275 sq. cm.
When a sector is folded into a cone, its area becomes the cone's curved surface, so the CSA equals the sector's area:
\[ \begin{aligned} \text{CSA} &= \frac{140}{360} \times \frac{22}{7} \times 15^{2} \\ &= \frac{7}{18} \times \frac{22}{7} \times 225 = 275 \end{aligned} \]
The radius of the circle becomes the slant height (15 cm) of the cone. 572, 527 and 257 are digit rearrangements of the answers and do not come from the formula.
No comment is present. Be the first to comment.
Loading…
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development