Question

100 POINTS 100 POINTS!

Answer 1

Answer:

Step-by-step explanation:

As each step has the same depth and rise, they are respectively 1.2/4=0.3m and 1.8/4=0.45m.

Dividing the steps along the dotted lines, the total rise of the 4 concrete steps  = (1+2+3+4)*0.45

= 4.5m

Total concrete volume = total rise * depth * width

= 4.5*0.3*1.8

= 2.43m^3

Answer 2

Answer:

Step-by-step explanation:

a much easier way - imagine there is another concrete stair exactly the same size and shape. flip it over n put it on top of this stair.

the pair will form a concrete block of 1.2m length, 1.8m width and (1.8+1.8/4)m height.

volume of the pair = 1.2*1.8*(1.8+1.8/4)

= 4.86m^3

so volume of concrete for 1 stair = 4.86/2 = 2.43m^3