Question

Use the conditional: If $\overline{AB}$and $\overline{CD}$intersect, then $\overrightarrow{AB}$and $\overrightarrow{CD}$intersect.

Provide a counterexample to disprove the statement:

If $m\angle A$is less than 100, then $\angle A$is an acute angle.

Short answer

The required example is $m\angle A=91°$.

Step-by-step solution

Step 1. Definition of acute angle.

The angle having the measurement below $90°$represents itself as an acute angle

Step 2. Consider a measurement of given angle.

Consider that $90°$represents the measurement of $\angle A$. As it is below $100°$but above $90°$so this makes the given condition false because it is not according to the definition of an acute angle.

Step 3. Make the conclusion.

As the example $m\angle A=91°$makes the provided condition false so this is the required example.