find the area of inner surface of the boundary wall

Question

for a rectangular plot of land measuring 45m ad 30m.  a boundary wall of height 2.4m is built all around the plot at a distance of 1m from the plot

Answer 1

If the wall is 1m from the plot, then it would be a rectangle outside the plot, and its dimensions would be 47m by 32m. 

 

The surface area of each section of the wall would be the length of that section times the height.  But if you look at the entire wall, you realize that the total area would just be the wall's perimeter times its height.

 

The perimeter is 2 (l + w) = 2 (47 + 32) = 2 * 79 = 158 m.

 

Multiplying that times the height results in 158 * 2.4 = 379.2 square meters.