The angles diagonally opposite each other are congruent while those adjacent to each other add up to 180 degrees. You can get eight congruent angles with a transversal if the two lines are parallel, because each angle would be 90.
Answer: 6x-3
Step-by-step explanation: Say that the third side is y. The equation for the perimiter is side 1+ side 2+ side 3= perimeter which if you intput what we have turns out like (10x+2) +(8x-1)+y=24x-2. If you add 10x+2 and 8x-1 you get 18x+1. We can update the previous equation making it (18x+1)+y=24x-2. Since your trying to find y, you isloate it by subtracting (18x+1) from both sides. This leaves us with y=6x-3 as the length of thr missing side.
For this case we have to:
x: Represents the unknown number
y: Represents the exponent of base 10
So, considering a system of equations we have:

From the first equation we have:

Substituting in the second equation:

We choose the positive value:

So, the number is 0.4.
So:

Thus, the exponent is 5.
Answer:
Yara use 0.4 and