Answer:
6000 square millimeters
Step-by-step explanation:
Side length of the slanting side can be calculated using the Pythagorean theorem,
L = sqrt(30^2+40^2) = 50
sufrace area of a triangular prism
= surface area of the end sections + the surface area of the three side faces
= 2*(30*40/2) + 40*(30+40+50)
= 1200 + 4800
= 6000 mm^2
28 divided by 1.0000 is 20
About 2 minutes and 33 seconds?
[ I apologize if this is wrong ]