互餘

互余
hùyú

to be complementary angles

Wiktionary

Entry Composition

1 互 hù mutual
=2 餘 yú
  1. extra
  2. surplus
  3. remaining
  4. remainder after division
  5. (following numerical value) or more
  6. in excess of (some number)
  7. residue (math.)
  8. after
  9. I
  10. me
=2 餘 Yú surname Yu
=2 餘 yú variant of 餘 yú, remainder
=2 餘 yé only used in 緒餘／绪余 (xùyú)