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Grade 6

Biology

MATHEMATICS

Physics

Chapters in CONCISE Mathematics - Middle School - 6

Exercises in Properties of Angles and LINES (Including Parallel Lines)

Question 2

Q2)

Each figure given below shows a pair of parallel lines cut by a transversal For each case, find a and b, giving reasons.

Solution

Transcript

Solution:

(i) a + 140° = 180° (Linear pair)

a = 180° - 140° = 40°

But b = a (Alternate angles)

= 40°

a = 40°, b = 40°

(ii) l II m and p intersects them

b + 60° = 180°

b = 180° - 60° = 120°

And a = 60° (Corresponding angle)

a = 60°, b = 120°

(iii) a = 110° (Vertically opp. angles)

b = 180° - a (Co-interior angle)

= 180° - 110° = 70°

(iv) a = 60° (Alternate int. angle)

b = 180° - a (Co-interior angle)

= 180° - 60° = 120°

(v) a = 72° (Alternate int. angles)

b = a (Vertically opp. angles)

i.e , b = 72

(vi) b = 100° (Corresponding angles)

a = 180° - b (Linear pair of angles)

a = 180° - 100° = 80°

(VII) a = 180° - 130° = 50° (Co-interior angle)

b = 130° (Vertically opposite angles)

(viii) b = 62° (Corresponding angles)

a = 180 - °b (Linear pair of angles)

a = 180° - 62° = 118°

(ix) a = 180° - 90° ( Linear pair of angles)

= 90°

b = 90° (Corresponding angles)