We know that <5 and <7 are supplementary. <7 and <9 are also supplementary because it is

given that <5 and <7 are supplementary and <7 and <9 are also supplementary. This means that the sum of the measures of <5 and <7 is equal to 180 degrees, and the sum of the measures of <7 and <9 is also equal to 180 degrees.

Supplementary angles are angles that add up to 180 degrees. In this case, since <5 and <7 are supplementary, their measures must add up to 180 degrees. Similarly, since <7 and <9 are supplementary, their measures must also add up to 180 degrees.

So, we can conclude that <5 + <7 = 180 degrees and <7 + <9 = 180 degrees.

given that angles <5 and <7 are supplementary, and angles <7 and <9 are also supplementary. We can conclude that angle <5 and angle <9 are also supplementary.

This is based on the property that if two angles are each supplementary to a third angle, then they are supplementary to each other.

given that <5 and <7 are supplementary. To prove that <7 and <9 are supplementary, we can use the Transitive Property.

The Transitive Property states that if two angles are each supplementary to a third angle, then they are supplementary to each other.

So, to prove that <7 and <9 are supplementary, we first need to prove that <5 and <9 are each supplementary to a third angle. Let's call this third angle <A.

Given that <5 and <7 are supplementary, we can say that:

<5 + <7 = 180°

Now, to prove that <5 and <9 are each supplementary to angle <A, we can say that:

<5 + <A = 180° ......(1)
<9 + <A = 180° ......(2)

From equation (1), we can isolate <A:

<A = 180° - <5

Substituting this value of <A into equation (2), we get:

<9 + (180° - <5) = 180°

Simplifying this equation, we have:

180° - <5 + <9 = 180°

Rearranging terms, we get:

<9 - <5 = 0°

Which then leads to:

<9 = <5

Now, we can conclude that <5 and <9 are supplementary to angle <A. Therefore, by the Transitive Property, we can say that <7 and <9 are also supplementary.

This proof shows that <7 and <9 are supplementary angles based on the given information.