An open cone with base radius 28cm and perpendicular height 96cm was stretched to form sector of a circle. calculate the arc of the sector (Take \(\pi = \frac{22}{7}\))
A
8800cm2
B
8448cm2
C
4400cm2
D
4224cm2
Verified Correct Answer: A.
Step-by-Step Mathematical Solution
L2 = 962 + 282
= 9216 + 784
= 10000
L = \(\sqrt{10000}\)
= 100cm
curved surface area = \(\pi r l\)
= \(\frac{22}{7} \times 28 \times 100\)
= 8800cm2
area of cone = area of sector
area of sector = 8800cm2
Source: Myschool Past Questions Archive (Record #36908)