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The base of a pyramid is a square of side 8cm. If its vertex is…

The base of a pyramid is a square of side 8cm. If its vertex is directly above the centre, find the height, given that the edge is 4.3cm
  • A.
    6cm
  • B.
    5cm
  • C.
    4cm
  • D.
    3cm
Correct Answer: Option C
Explanation

Base of pyramid of a square of side 8cm vertex directly above the centre edge = (4sqrt{3})cm
From the diagram, the diagonal of one base is AC2 = 82 + 82
Ac2 = 64 + 64 = 128
AC = (8sqrt{2})
but OC = (frac{1}{2})AC = 8(sqrt{frac{2}{2}}) = (4sqrt{2})cm
OE = h = height
h2 = ((4sqrt{3}))2
16 x 2 – 16 x 2
48 – 32 = 16
h = (sqrt{16})
= 4