<PRE><B>Question 1062168</B>
All side faces are the same in this problem
:
surface area(SA) = area of base(A) + ( (1/2) * perimeter of base * slant length )
:
The base is an equilateral triangle with sides 12.9 cm
:
height = square root ( (12.9)^2 - (6.45)^2 ) = 11.17
:
A = 2 * (1/2) * 6.45 * 11.17 = 72.05
:
SA = 72.05 + ( (1/2) * 3 * 12.9 * 7.2 ) = 211.37 cm^2
:
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