Answer:
BC = 3
Explanation:
given B is between A and C , then
AB + BC = AC ← substitute AC = 8
AB + BC = 8
subtract BC from both sides
AB = 8 - BC → (1)
given C is between B and D , then
BC + CD = BD ← substitute BD = 11
BC + CD = 11
subtract BC from both sides
CD = 11 - BC → (2)
Then
AB + BC + CD = AD ← substitute AD = 16
AB + BC + CD = 16
substitute values for AB and CD from (1) and (2) above
8 - BC + BC + 11- BC = 16 ← collect like terms on left side
19 - BC = 16 ( subtract 19 from both sides )
19 - 19 - BC = 16 - 19 ( simplify )
- BC = - 3 ( multiply both sides by - 1 )
BC = 3