Answer:
[tex]40 in^2[/tex]
Step-by-step explanation:
The initial dimensions of the paper are:
[tex]L=10 in[/tex] (length)
[tex]W=8 in[/tex] (width)
After the paper is cut along the diagonal, we remain with a right triangle, of which the length and the width corresponds to the base and the height.
For a triangle, the area is calculated as
[tex]A=\frac{1}{2}bh[/tex]
where
b is the base
h is the height
Here we have:
[tex]b=L=10 in\\h=W=8 in[/tex]
Therefore, the area of the triangle is:
[tex]A=\frac{1}{2}(10)(8)=40 in^2[/tex]