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Wednesday, 04 March 2026
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Find the value of l in the frustrum above



Find the value of l in the frustrum above
Take Free Practice Test On 2026 JAMB UTME, Post UTME, WAEC SSCE, GCE, NECO SSCE
  • A 5cm
  • B 6cm
  • C 7cm
  • D 8cm
Correct Answer: Option A
Explanation:

ΔABE and ΔACD are similar∴ x [table]= 3
6




x+4
[/table]



6x = 3(x+4)
6x = 3x + 12
3x = 12
x = 4
In ΔACD; L2 = (4+4)2 + 62
= 82 + 62
= 64 + 36
= 100L =
√ 100Â
= 10cm
In ABE, AE2 = 42 + 32
= 16 + 9
= 25
AE = 5cm
∴L = 10 - 5
= 5cm

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