https://socratic.org/questions/a-pyramid-has-a-parallelogram-shaped-base-and-a-peak-directly-above-its-center-i-123
l = 9, b = 6, theta = (5pi)/12, h = 9l=9,b=6,θ=5π12,h=9
"To find the Total Surface Area T S A"To find the Total Surface Area T S A
"Area of parallelogram base " A_B = l b sin thetaArea of parallelogram base AB=lbsinθ
A_B = 9 * 6 * sin ((5pi)/12) = 52.16AB=9⋅6⋅sin(5π12)=52.16
S_1 = sqrt(h^2 + (b/2)^2) = sqrt(9^2 + 3^2) = 9.49S1=√h2+(b2)2=√92+32=9.49
S_2 = sqrt(h^2 + (l/2)^2) = sqrt(9^2 + (9/2)^2) = 10.06S2=√h2+(l2)2=√92+(92)2=10.06
"Lateral Surface Area " A_L = 2 * ((1/2) l * S_1 + (1/2) b * S_2Lateral Surface Area AL=2⋅((12)l⋅S1+(12)b⋅S2
A_L = (cancel2 * cancel(1/2)) * (l * S_1 + b * S_2) = (9 * 9.49 + 6 * 10.06)
A_L = 145.77
color(maroon)("Total Surface Area " A_T = A_B + A_L = 52.16 + 145.77 = 197.93