Which of the following represent the addition property of equality? if a = b and c = d, then a + c = b + d. if a = b and c = d, then ac = bd. if a = b and c = d, then ac + b = bd + a. if a = b and c = d, then a + b = c + d.

Correct answer is A.
If a = b and c = d, then a + c = b + d.
                              

Volume is length times width times height so
20 times 8 times 30 which is 4,800
surface area is ph (p is perimeter of base), h is height.
so perimeter would be length+length+width+width so 20+20+8+8 which is 56. so multiply 56 times 30 which is 1680. hope this !