A pyramid has a parallelogram shaped base and a peak directly above its center. Its base's sides have lengths of 3 3 and 2 2 and the pyramid's height is 3 3. If one of the base's corners has an angle of pi/4 π4, what is the pyramid's surface area?

1 Answer
Jun 8, 2018

color(indigo)(T S A = L S A + A_(base) = 19.98 + 4.24 = 24.22TSA=LSA+Abase=19.98+4.24=24.22 sq units

Explanation:

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"Total Surface Area of Pyramid " T S A = L S A + A_(base)Total Surface Area of Pyramid TSA=LSA+Abase

l = 3, b = 2, theta = pi/4, h = 3l=3,b=2,θ=π4,h=3

S_1 = sqrt (h^2 + (b/2)^2) = sqrt(3^2 + 1^2) = sqrt 10 = 3.16S1=h2+(b2)2=32+12=10=3.16

S_2 = sqrt (h^2 + (l/2)^2) = sqrt(3^2 + (1.5)^2) = sqrt (11.25) = 3.5S2=h2+(l2)2=32+(1.5)2=11.25=3.5

L S A = 2((1/2) l * S_1 + (1/2) b * S_2) = l*S_1 + b*S_2LSA=2((12)lS1+(12)bS2)=lS1+bS2

L S A = 3 * 3.16 + 3 + 3.5 = 19.98LSA=33.16+3+3.5=19.98

A_(base) = l b sin theta = 3 * 2 * (1/sqrt2) = 3 sqrt2 = 4.24Abase=lbsinθ=32(12)=32=4.24

color(indigo)(T S A = L S A + A_(base) = 19.98 + 4.24 = 24.22TSA=LSA+Abase=19.98+4.24=24.22 sq units