Question

Question 1. Determine whether the biconditional statement is true or false. If false, give a counterexample.

An angle is a straight angle if and only if it is not acute.


A. false; m∠1 = 180°, ∠1 is not an acute angle
B. true
C. false; m∠1 = 63°, ∠1 is not a straight angle
D. false; m∠1 = 102°, ∠1 is not a straight angle

Question 2. Determine whether the biconditional statement is true or false. If false, give a counterexample.

An angle is a right angle if and only if it is not obtuse.


1. false; m∠1 = 70°, ∠1 is not a right angle
2. false; m∠1 = 90°, ∠1 is not an obtuse angle
3. true
4. false; m∠1 = 120°, ∠1 is not a right angle

Answer 1

Q1

It is false as straight angle is not acute, obtuse or right.

Correct choice is

• D. false; m∠1 = 102°, ∠1 is not a straight angle

Q2

It is false as right angle is not acute, obtuse or straight.

Correct choice is

• 1. false; m∠1 = 70°, ∠1 is not a right angle.