Complementary angles have a sum of 90° (they are two angles that add up to make a right angle).
Let's say one of these angles has a measure

. The program states that its complement is eight times this, so it has measure

.
We know that these angles together equal 90°, so we can write

.
If x = 10, then the first angle has a measure of 10°, and the second angles has a measure of

, or 80°.