A pyramid has a base in the shape of a rhombus and a peak directly above the base's center. The pyramid's height is 8 8, its base has sides of length 6 6, and its base has a corner with an angle of (3 pi)/4 3π4. What is the pyramid's surface area?

1 Answer
Oct 11, 2017

Surface area of pyramid with rhombus base = 127.9839

Explanation:

Opposite base angles of the rhombus are (3pi)/4 & pi/43π4&π4 respy.
d1 & d2d1&d2 be the two diagonals intersecting at right angle.
sin (theta/2) = sin ((pi/4)/2) = sin (pi/8)=((d1/2)/6)sin(θ2)=sin(π42)=sin(π8)=(d126)
sin(pi/8)=d1/12 or d1=12*sin(pi/8)=sin(π8)=d112ord1=12sin(π8)=4.5922

Similarly,cos(pi/8)=((d2/6)/2)=(d2/12)cos(π8)=(d262)=(d212)
d2=12*cos(pi/8)=d2=12cos(π8)=11.0866

Area of Rhombus base =(d1*d2)/2=(4.5922*11.0866)/2==d1d22=4.592211.08662=25.4559

Height of one side surface h1=sqrt((b/2)^2+h^2)h1=(b2)2+h2
As b/2=6/2=3, h1=sqrt(3^2+8^2)=8.544b2=62=3,h1=32+82=8.544

Area of 4 sides of pyramid =4*(1/2)b*h1=2*6*8.544==4(12)bh1=268.544=102.588

Surface area of pyramid = base area + 4 side areas
#=25.4559+102.588=127.9839
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