A pyramid has a parallelogram shaped base and a peak directly above its center. Its base's sides have lengths of 9 9 and 6 6 and the pyramid's height is 9 9. If one of the base's corners has an angle of (5pi)/125π12, what is the pyramid's surface area?

1 Answer
Jul 4, 2018

color(maroon)("Total Surface Area " A_T = A_B + A_L = 52.16 + 145.77 = 197.93Total Surface Area AT=AB+AL=52.16+145.77=197.93

Explanation:

https://socratic.org/questions/a-pyramid-has-a-parallelogram-shaped-base-and-a-peak-directly-above-its-center-i-123https://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=96sin(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)lS1+(12)bS2

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