Answer
A) 2160 cubic inches
Step by step explanation
Volume of a rectangular prism = length *width*height.
The give figure (stairway) consists of two rectangular prism.
The volume of the first rectangular prism (bigger one) = 12 *10*12
=120*12
1 st prism = 1440 cubic inches
The volume of the rectangular prism 2 (smaller one) = 12*10*6
=120*6
The volume of the rectangular prism 2 = 720 cubic inches
The volume of the concrete stairway = Volume of the prism 1 + Volume of the prism 2
= 1440 + 720
The volume of the concrete stairway = 2160 cubic inches.
Thank you.