Q15 of 115 Page 8

In Fig 8.115, ∠1=60° and ∠2= if a right angle. Prove that l||m.

Given,

∠1 = 60^o

∠2 = of right angle

To prove: l ‖ m

Proof: ∠1 = 60^o

∠2 = * 90^o = 60^o

Since, ∠1 = ∠2 = 60^o

Therefore, l ‖ m as pair of corresponding angles are equal.

Two unequal angles of a parallelogram are in the ratio 2 : 3. Find all its angles in degrees.

If each of the two lines is perpendicular to the same line, what kind of lines are they to each other?

In Fig 8.116, if l||m||n and ∠1 = 60°, find ∠2

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