She would sell it for $26.60 after the markup.
Answer:
5.50
Step-by-step explanation:
I am smart
M= y2-y1/x2-x1
Line 1: 3-(-5) / 0-4 = -2
Line 2: 5-11 / (-1)-(-4) = -2
Since the slopes are the same they are parallel

Here, we want to find the diagonal of the given solid
To do this, we need the appropriate triangle
Firstly, we need the diagonal of the base
To get this, we use Pythagoras' theorem for the base
The other measures are 6 mm and 8 mm
According ro Pythagoras' ; the square of the hypotenuse equals the sum of the squares of the two other sides
Let us have the diagonal as l
Mathematically;
![\begin{gathered} l^2=6^2+8^2 \\ l^2\text{ = 36 + 64} \\ l^2\text{ =100} \\ l\text{ = }\sqrt[]{100} \\ l\text{ = 10 mm} \end{gathered}](https://tex.z-dn.net/?f=%5Cbegin%7Bgathered%7D%20l%5E2%3D6%5E2%2B8%5E2%20%5C%5C%20l%5E2%5Ctext%7B%20%3D%2036%20%2B%2064%7D%20%5C%5C%20l%5E2%5Ctext%7B%20%3D100%7D%20%5C%5C%20l%5Ctext%7B%20%3D%20%7D%5Csqrt%5B%5D%7B100%7D%20%5C%5C%20l%5Ctext%7B%20%3D%2010%20mm%7D%20%5Cend%7Bgathered%7D)
Now, to get the diagonal, we use the triangle with height 5 mm and the base being the hypotenuse we calculated above
Thus, we calculate this using the Pytthagoras' theorem as follows;
6x+4=4x-2 subtract four x to get 2x+4=-2 and subtract 4 and get -6 and divide it by two to get -3