i. AC = 9 cm [Given]
Points X and Y are the midpoints of sides AB and BC respectively. [Given]
∴ XY = (1/2) AC [Midpoint tfyeprem]
= (1/2) x 9 = 4.5 cm
ii. AB = 5 cm [Given]
Points Y and Z are the midpoints of sides BC and AC respectively. [Given]
∴ YZ = (1/2) AB [Midpoint theorem]
= (1/2) x 5 = 2.5 cm
iii. BC = 11 cm [Given]
Points X and Z are the midpoints of sides AB and AC respectively. [Given]
∴ XZ = (1/2) BC [Midpoint theorem]
= (1/2) x 11 = 5.5 cm
l(XY) = 4.5 cm, l(YZ) = 2.5 cm, l(XZ) = 5.5 cm