Big Ideas Math Integrated I, 2016
BI
Big Ideas Math Integrated I, 2016 View details
5. Proving Geometric Relationships
Continue to next subchapter

Exercise 24 Page 485

Consider the definition of perpendicular lines.

See solution.

Practice makes perfect
Let's take a look at the given information and the desired outcome of the proof.
Let's now consider the given diagram.
rectangle

Recall the definition of perpendicular lines. Since we know that is perpendicular to and that is perpendicular to we can conclude that both and are right angles. This means that they measure

By the definition of perpendicular lines and

Next, we are given that and are congruent angles, and that and are also congruent angles. Therefore, we can state that the measures of and are equal, as well as the measures of and

By the definition of congruent angles and

We can now find the measures of and by using the Transitive Property of Equality.
We found that both and measure

By the Transitive Property of Equality and

Finally, we will use the definition of perpendicularity one last time. If an angle between two segments or lines is a right angle, then these segments or lines are said to be perpendicular. Therefore, is perpendicular to and is pependicular to

By the definition of perpendicularity, and

Now let's gather all of the statements we wrote to formulate a paragraph proof.

Completed Proof

Considering the given information, we can summarize all the steps in a paragraph proof.
Proof. By the definition of perpendicular lines, the measure of and is Next, by the definition of congruent angles, and have the same measure, and and have the same measure. By the Transitive Property of Equality, and measure Then, by the definition of perpendicular lines, is perpendicular to and is perpendicular to