Q7 of 115 Page 8

In Fig 8.111, state which lines are parallel and why?

∠EOC = ∠DOK = 100^o(Vertically opposite angle)

∠DOK = ∠ACO = 100^o(Vertically opposite angle)

Here two lines, EK and CA cut by a third line L and the corresponding angles to it are equal.

Therefore,

EK ‖ AC

In Fig 8.109, if AB ||CD and CD||EF, find ∠ACE.

In Fig 8.110, PQ||AB and PR||BC. If ∠QPR = 102°, determine ∠ABC. Give reasons.

In Fig 8.112, if l||m, n||p and ∠1 =85°, find ∠2.

If two straight lines are perpendicular to the same line, prove that they are parallel to each other.