I hate rounding.
Let's call the diagonal x. It's the hypotenuse of the right triangle whose legs are the rectangle sides.
According to the problem we have a length x-4 and a width x-5 and an area
82 = (x-4)(x-5)
82 = x^2 - 9x + 20
0 = x^2 - 9x - 62
That one doesn't seem to factor so we go to the quadratic formula

Only the positive value makes any sense for this problem, so we conclude

That's the exact answer. Did I mention I hate rounding? That's about
x = 13.6 meters
Answer: 13.6
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It's not clear to me this problem is consistent. By the Pythagorean Theorem the diagonal satisfies

which works out to

That's not consistent with the first answer; this problem really has no solution. Tell your teacher to get better material.
Unsure of what you are asking!
But if the issue here is how to define a line segment, write what you do know and then reconsider "undefined terms."
A line segment is a straight line that connects a given starting point and given ending point.
If you consider a circle of radius 3 units, the radius can be thought of as the line segment connecting the center of the circle to any point on the circumference of the circle.
If the center of a given circle is at C(0,0) and a point on the circumference is given by R(3sqrt(2),3sqrt(2)), then AC is the line segment joining these two points. This line segment has length 3 and is in the first quadrant, with coordinates x=3sqrt(2) and y=3sqrt(2) describing the end point of the segment.
The probability that the next 4 winners will all be 7th grade students is 3/4
<span>90/x=100/18</span>
<span>(90/x)*x=(100/18)*x - </span> multiply both sides of the equation by x
<span>90=5.55555555556*x - </span>divide both sides of the equation by (5.55555555556) to get x
<span>90/5.55555555556=x </span>
<span>16.2=x </span>
<span>x=16.2</span>
<span>18% of 90=16.2
</span><span>
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<span>2 ln 8 + 3 ln y simplifies to ln 8^2 + ln y^3, which in turn simplifies to
ln 64/y^3, or ln {64*y^3}</span>