Answer:
Option D
Step-by-step explanation:
Given are the four options and we have to select the one which is not good defintion.
A)A whole number is even if and only if it is divisible by 2.
--- Is correct definition of even number.
B. A whole number is odd if and only if the number is not divisible by 2.
--- Correct definition
C. An angle is straight if and only if its measure is 180.
... correct definition
D. A ray is a bisector of an angle if and only if it splits the angle into two angles
... This is incorrect because congruent/equal angles should be there
Correct definition is
A ray is a bisector of an angle if and only if it splits the angle into two congruent angles
Answer:
Option D.
Step-by-step explanation:
A biconditional statement are the statement in which both parts have the same truth value. It is written in the form of "p if and only if q".
First statement: A whole number is even if and only if it is divisible by 2.
This statement is a biconditional statement because it is the definition of even numbers and have the same truth value.
Second statement: A whole number is odd if and only if the number is not divisible by 2.
This statement is a biconditional statement because it is the definition of odd numbers and have the same truth value.
Third statement: An angle is straight if and only if its measure is 180.
This statement is a biconditional statement because it is the definition of straight angle and have the same truth value.
Fourth statement: A ray is a bisector of an angle if and only if it splits the angle into two angles.
This statement is not a biconditional statement because if a ray splits the angle into two angles, then it is not necessary that it is a bisector.
Definition of bisector: A ray is a bisector of an angle if and only if it splits the angle into two congruent angles.
Therefore, the correct option is D.
