Answer:Vertical angles are formed by intersecting lines and are always congruent. In this case, ZA and ZB are vertical angles, so their measures are equal.
Given that the measure of angle A (m/A) is 90°, and m/B is expressed as (5x), we can set up an equation using the fact that ZA and ZB are vertical angles:
�
/
�
=
�
/
�
m/A=m/B
90
°
=
5
�
90°=5x
Now, solve for x:
5
�
=
90
5x=90
Divide both sides by 5:
�
=
90
5
x=
5
90
�
=
18
x=18
So, the value of x is 18.
Explanation: