Answer:
4x deg = 72deg
Explanation:
these straight lines intersect and form 4 angles, all of which actually add up to 360 degrees! the key here is to look and actually determine that the two angles which are given measurements are actually equal to each other in the intersecting line system. take the line that goes from 4 o'clock to 10 o'clock. the other line sticks through and forms 2 angles, one that's greater than 90 that's unlabeled, and the 90-x angle, which is acute. Now look on the other side, and you see the very same thing. The same obtuse (>90 deg) angle, unlabeled, and a 4x acute angle. The key is realising that their measurements are the same, and that 4x = 90 - x
From there it's simple math and it comes out to 4x + x = 90, so 5x = 90, x = 18.
Now it asks for 4x deg, 4*18 = 72, so 72deg final answer
(just type 72 into the box, they give you degrees)