1:
A has volume 9*6*5=270 and surface area 2*(9*6+9*5+6*5)=258.
B has volume 9*3*10=270 and surface area 2*(9*10+9*3+3*10)=294.
D is the correct answer.
2: The surface area is 2*(6*8+6*13+8*13)=460.
3: The area of one of the triangular areas is 5*24/2=60, the area of one of the upper rectangles is 13*16=208, and the area of the lower one is 16*24=384.
There are two triangles, two upper rectangles, and one lower rectangle, so we have a total of 60*2+208*2+384=920.
4: The bottom square has area 30*30=900, and each upper triangle has area 30*45/2=675. We have four triangles and one square, so our answer is 675*4+900=3600.