Notice how that slant line intersects two parallel lines. The angle between the slant line and the upper horizontal line is <4. Now if you start there and move along the slant line, just past the 158 degree angle, you have another angle, this one equal to <4 (corresponding angles). Call it <5.
Now the 158 degree angle and 5 are "supplementary angles;" they add up to 180 degrees. Thus, 5 is (180-158), or 22 degrees. Since <5 = <4,
>4 = 22 degees (answer).