Plane Geometry
- In the given, AB || CD. Then X is equal to:
-
View Hint View Answer Discuss in Forum
Through O, draw a line l parallel to both AB and CD. Then
∠1 = 45° (alt. ∠S)
and ∠2 = 30° (alt. ∠S)
∴ ∠BOC = ∠1 + ∠2 = 45° + 30° = 75°Correct Option: E
Through O, draw a line l parallel to both AB and CD. Then
∠1 = 45° (alt. ∠S)
and ∠2 = 30° (alt. ∠S)
∴ ∠BOC = ∠1 + ∠2 = 45° + 30° = 75°
So, X = 360° – ∠BOC = 360° – 75° = 285°
Hence X = 285°.
- An angle is equal to one-third of its supplement. Its measure is equal to :
-
View Hint View Answer Discuss in Forum
Let the measured of the required angle be P degree.
Then, its supplement = 180 – P
Now use the formula,Angle = 1 ( its supplement ) 3 Correct Option: C
Let the measured of the required angle be P degree.
Then, its supplement = 180 – P
Now use the formula,Angle = 1 ( its supplement ) 3 P = ( 180 - P ) 3
3P + P 180°
⇒ P = 45°
- In the adjoining figure, AB || CD, t is the traversal, EG and FG are the bisectors of ∠BEE and ∠DFE respectively, then ∠EGF is equal to :
-
View Hint View Answer Discuss in Forum
AB || CD and t transversal intersects them at E and F
∠BEF + ∠EFD = 180° (co-interior angles)⇒ 1 ∠BEF + 1 ∠EFD = 180/2 2 2
⇒ ∠FEG + ∠EFG = 90°
In Δ GEF
∠EGF + ∠FEG + ∠EFG = 180°
Correct Option: A
AB || CD and t transversal intersects them at E and F
∠BEF + ∠EFD = 180° (co-interior angles)⇒ 1 ∠BEF + 1 ∠EFD = 180/2 2 2
⇒ ∠FEG + ∠EFG = 90°
In Δ GEF
∠EGF + ∠FEG + ∠EFG = 180°
∴ ∠EGF + 90° = 180°
∴ ∠EGF = 90°.
The above result can be restated as :
If two parallel lines are cut by a traversal, then the bisectors of the interior angles on the same side of the traversal intersect each other at right angles.
- Find the measure of an angle, if six times its complement is 12° less than twice its supplement :
-
View Hint View Answer Discuss in Forum
Let, the measure of the required angled be A°.
Then, measure of its complement = ( 90 – A )° measure of its supplement = (180 – A)°
According to question,
6(90° – A) = 2(180° – A) –12°Correct Option: A
Let, the measure of the required angled be A°.
Then, measure of its complement = ( 90 – A )° measure of its supplement = (180 – A)°
According to question,
6(90° – A) = 2(180° – A) –12°
⇒ 540° – 6A = 360° – 2A – 12°
⇒ 4A = 192°
⇒ A = 48°.
- In fig., AB || CD, ∠a is equal to:
-
View Hint View Answer Discuss in Forum
CD || AB (Given)
Produce RQ to meet AB in S
∠CRS = ∠PSR (at. int. ∠s)
But ∠CRS = 55°
∴ ∠PSR = 55°
Correct Option: A
CD || AB (Given)
Produce RQ to meet AB in S
∠CRS = ∠PSR (at. int. ∠s)
But ∠CRS = 55°
∴ ∠PSR = 55°
Now in QSP
∠QSP + ∠QPS + ∠PQS = 180°
55° + 38° + ∠SQP = 180°
∴ ∠SQP = 180° – 93° = 87°
But angle a and ∠PQS are linear
∠a = 180° – 87°
∠a = 93°