We want to find the total area that Sakura will paint. Based on the given figure, the side walls have the dimension of 10 in by 6 in while the front and back walls have the dimension of 10 in by 10 in. Basically, we want to sum up the total area of these 4 walls to get the total area that Sakura will paint.
The side walls represent a rectangle. The area of the rectangle can be computed via the equation
[tex]A_{rec\tan gle}=lxw[/tex]Hence, the area of one side wall is equal to
[tex]A_{sidewall}=10\times6=60in^2[/tex]For two side walls, we just multiply the area of one sidewall by 2, having
[tex]2\times A_{sidewall}=120in^2[/tex]We are left with the back wall and front wall of the birdhouse. We can say that they have the same dimension but the front wall has a hole that will not be painted. The dimensions of the front and back wall are 10 in x 10 in. Hence, for the back wall, which doesn't have any opening, the total area would be
[tex]A_{backwall}=10\times10=100in^2[/tex]For the front wall, you have an opening with a dimension of 4 in by 5 in. The area of the opening, or the door, is
[tex]A_{door}=4\times5=20in^2[/tex]The total area for the front wall would be the area of the back wall minus the area of the door of the birdhouse. Hence, we have
[tex]A_{frontwall}=100in^2-20in^2=80in^2[/tex]The total area that Sakura paint is just the sum of the areas of the four outside walls, which is just represented in mathematical expression as
[tex]A_{tot}=2A_{sidewall}+A_{backwall}+A_{frontwall}_{}[/tex]Substitute the computed area of the walls on the expression above and compute, we get
[tex]A_{tot}=120in^2+80in^2+100in^2=300in^2[/tex]Therefore, the answer is the letter C.
