Q8 of 115 Page 8

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

Corresponding angles are equal so,

∠1 = ∠3 = 85^o

By using co-interior angle property,

∠2 + ∠3 = 180^o

∠2 + 85^o = 180^o

∠2 = 95^o

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

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

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

Prove that the two arms of an angle are perpendicular to the two arms of another angle, then the angles are either equal or supplementary.