Can two acute angles be vertical, adjacent, complementary, or supplementary?

Two acute angles can be vertical,adjacent,complementary.

They cannot be supplementary.

Two angles ##/_A## are vertical (formed by two intersecting lines) and acute (smaller than ##90^o##).

Angles ##/_1## and ##/_2## are adjacent (share one side) and acute.

Angles ##/_a## and ##/_b## are complimentary (sum of them equals to ##90^o##) and acute.

Two acute angles cannot be supplementary (sum of them should equal to ##180^o##) because each of them is smaller than ##90^o##.