To solve for \( x \) in the two adjacent angles that make up a 90° angle, we have:
- The first angle: \( x \)°
- The second angle: \( (x + 30) \)°
Since these two angles add up to 90°, we can set up the equation:
\[ x + (x + 30) = 90 \]
Now, simplify the equation:
\[ 2x + 30 = 90 \]
Next, subtract 30 from both sides:
\[ 2x = 60 \]
Now, divide by 2:
\[ x = 30 \]
So the measure of \( x \) is \( 30 \)°.
The answer is 30.