Which counterexample disproves the conjecture? a student concludes that if x is a real number, then x ≥ x^3. a. x= 3 b. x= 1 c. x= 0 d. x= -1

Let's check all x for satisfiyng the inequality :
1. x=3, then the inequality is false;
2. x=1, then the inequality is true;
3. x=0, then the inequality is true;
4. x=-1, then the inequality is true.

counterexample A disproves the conjecture.

If the diameter is 8 than the radius is 4 because 2r or 2*radius equals the diameter. 4*2=8. 8/2=4.