Answer:
y = 102° , z = 75°
Step-by-step explanation:
Assuming this is geometry, you must find the value of 'z' first.
Using the [Supplementary Angles Theorem] for 'z' :
105° + z = 180°
Solve for z.
z = 75°
You may also hear that those two angles are a 'Linear Pair'
Then using the formula for: [Sum of Internal Angles]
Which is: sum = (n-2) * 180° where 'n' is the number of sides
The total sum of internal angles of a quadrilateral is 360°
Now knowing 3 of the 4 interior angles, you can just do arithmetic:
99° + 84° + 75° + y = 360°
Simplify:
258° + y = 360°
Therefore:
y = 102°
