Question

Tolong bantuannya yaa , makasih no 17 sama 18 makasih

Answer 1

Ac² = bc² + ab² - 2bc(ab) x cos120derajat
    = 144 + 100 + 2 (12)( 10) x -1/2
   = 244 - 120
  = 364
  = 2 √91

Cos = km² + ml² - (kl)² / ( 2(ml) (km) )
      = 4² + 3² - (√37)² / 2 (3)(4)
      = 16 + 9 - 37 / 24
     = 25 - 37 / 24
    = -12/24
   = -1/2
Cos = -1/2 = 120 derajat