A pyramid has a parallelogram shaped base and a peak directly above its center. Its base's sides have lengths of 4 and 5 and the pyramid's height is 6 . If one of the base's corners has an angle of pi/3 , what is the pyramid's surface area?

1 Answer
Dec 20, 2017

T S A = 74.9435.

Explanation:

CH = 4 * sin (pi/3) = 3.4641
Area of parallelogram base = a * b1 = 5*3.4641 = color(red)(17.3205)

EF = h_1 = sqrt(h^2 + (a/2)^2) = sqrt(6^2+ (5/2)^2)= 6.5
Area of Delta AED = BEC = (1/2)*b*h_1 = (1/2)*4* 6.5= color(red)(13)#

EG = h_2 = sqrt(h^2+(b/2)^2 ) = sqrt(6^2+(4/2)^2 )= 6.3246
Area of Delta = CED = AEC = (1/2)*a*h_2 = (1/2)*5*6.3246 = color(red)( 15.8115)

Lateral surface area = 2* DeltaAED + 2*Delta CED
=( 2 * 13)+ (2* 15.8115) = color(red)(57.623)

Total surface area =Area of parallelogram base + Lateral surface area = 17.3205 + 57.623 = 74.9435

Total Surface Area # T S A = **74.9435**#enter image source here