Answer: Choice D. 8m, 9m, 10m
==================================
Step-by-step explanation:
If a = 8 and b = 9 are the two legs of a triangle and c = 10 is the hypotenuse, then
a^2 + b^2 = c^2
8^2 + 9^2 = 10^2
64 + 81 = 100
145 = 100
We get a false equation as 145 and 100 are two different values. So the original equation is false when (a,b,c) = (8,9,10)
By the converse of the pythagorean theorem, we have proven that this particular triangle is not a right triangle
-------------
Contrast this with something like choice A where we have a = 3, b = 4, c = 5 leading to
a^2 + b^2 = c^2
3^2 + 4^2 = 5^2
9 + 16 = 25
25 = 25
we get a true equation so a triangle with sides 3,4,5 is a right triangle. Choices B and C follow a similar path.