I have attached a screenshot with the complete question
Part (1):
We are given the prototype used for building the wall with the following dimensions:
long side = 8 in
short side = 5 in
Now, in the wall itself, we want to find the value of the length "a".
This length represents the short side in the prototype used in building the wall.
Therefore:
a = 5 in
Part (2):
We are given the prototype used for building the wall with the following dimensions:
long side = 8 in
short side = 5 in
Now, in the wall itself, we want to find the value of the length "b".
This length represents the long side in the prototype used in building the wall.
Therefore:
b = 8 in
Part (3):
Looking at Dakota's wall, we can note that its height is formed from three bricks each having the height "b". We have deduced previously that b = 8 in.
Therefore:
height of wall = 3 * b
height of wall = 3 * 8 = 24 in
Part (4):
Looking at Dakota's wall, we can note that its length is formed from nine bricks each having a length "a". We have deduced previously that a = 5 in.
Therefore:
length of wall = 9 * a
length of wall = 9 * 5 = 45 in
Hope this helps :)