Answer:
367,679
Again someone helped me with this question so you get the answer too.
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
----------
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.
<span> is the answer a Polygon</span>
The answer is Isosceles triangle
Answer:
(64,86.5)
Step-by-step explanation:
find the case where he gets 70 and the case where he gets 79
if his average is 70:
(75+62+85+2x)/5=70
(222+2x)/5=70
222+2x=350
2x=128
x=64
if his average is 79:
(75+62+85+2x)/5=79
(222+2x)/5=79
222+2x=395
222+2x=395
2x=173
x=86.5