RD Chapter 10- Congruent Triangles Ex-10.1 |
RD Chapter 10- Congruent Triangles Ex-10.2 |
RD Chapter 10- Congruent Triangles Ex-10.3 |
RD Chapter 10- Congruent Triangles Ex-10.4 |
RD Chapter 10- Congruent Triangles Ex-VSAQS |

One angle is equal to three times its supplement. The measure of the angle is

(a) 130°

(b) 135°

(c) 90°

(d) 120°

**Answer
1** :

Let required angle = x

Then its supplement = (180° – x)

x = 3(180° – x) = 540° – 3x

⇒ x + 3x = 540°

⇒ 4x = 540°

⇒ x == 135°

∴ Required angle = 135° (b)

Two straight lines AB and CD intersect one another at the point O. If ∠AOC + ∠COB + ∠BOD = 274°, then ∠AOD =

(a) 86°

(b) 90°

(c) 94°

(d) 137°

**Answer
2** :

Sum of angles at a point O = 360°

Sum of three angles ∠AOC + ∠COB + ∠BOD = 274°

∴ Fourth angle ∠AOD = 360° – 274°

= 86° (a)

Two straight lines AB and CD cut each other at O. If ∠BOD = 63°, then ∠BOC =

(a) 63°

(b) 117°

(c) 17°

(d) 153°

**Answer
3** :

CD is a line

∴ ∠BOD + ∠BOC = 180° (Linear pair)

⇒ 63° + ∠BOC = 180°

⇒ ∠BOC = 180° – 63°

∴ ∠BOC =117° (b)

Consider the following statements:

When two straight lines intersect:

(i) adjacent angles are complementary

(ii) adjacent angles are supplementary

(iii) opposite angles are equal

(iv) opposite angles are supplementary Of these statements

(a) (i) and (iii) are correct

(b) (ii) and (iii) are correct

(c) (i) and (iv) are correct

(d) (ii) and (iv) are correct

**Answer
4** :
Only (ii) and (iii) arc true. (b)

Given ∠POR = 3x and ∠QOR = 2x + 10°. If POQ is a striaght line, then the value of x is

(a) 30°

(b) 34°

(c) 36°

(d) none of these

**Answer
5** :

∵ POQ is a straight line

∴ ∠POR + ∠QOR = 180° (Linear pair)

⇒ 3x + 2x + 10° = 180°

⇒ 5x = 180 – 10° = 170°

∴ x = = 34° (b)

In the figure, AOB is a straight line. If ∠AOC + ∠BOD = 85°, then ∠COD =

(a) 85°

(b) 90°

(c) 95°

(d) 100°

**Answer
6** :

AOB is a straight line,

OC and OD are rays on it

and ∠AOC + ∠BOD = 85°

But ∠AOC + ∠BOD + ∠COD = 180°

⇒ 85° + ∠COD = 180°

∠COD = 180° – 85° = 95° (c)

In the figure, the value of y is

(a) 20°

(b) 30°

(c) 45°

(d) 60°

**Answer
7** :

In the figure,

y = x (Vertically opposite angles)

∠1 = 3x

∠2 = 3x

∴ 2(x + 3x + 2x) = 360° (Angles at a point)

2x + 6x + 4x = 360°

12x = 360° ⇒ x == 30°

∴ y = x = 30° (b)

In the figure, the value of x is

(a) 12

(b) 15

(c) 20

(d) 30

**Answer
8** :

∠1 = 3x+ 10 (Vertically opposite angles)

But x + ∠1 + ∠2 = 180°

⇒ x + 3x + 10° + 90° = 180°

⇒ 4x = 180° – 10° – 90° = 80°

x == 20 (c)

In the figure, which of the following statements must be true?

(i) a + b = d + c

(ii) a + c + e = 180°

(iii) b + f= c + e

(a) (i) only

(b) (ii) only

(c) (iii) only

(d) (ii) and (iii) only

**Answer
9** :

In the figure,

(i) a + b = d + c

a° = d°

b° = e°

c°= f°

(ii) a + b + e = 180°

a + e + c = 180°

⇒ a + c + e = 180°

(iii) b + f= e + c

∴ (ii) and (iii) are true statements (d)

If two interior angles on the same side of a transversal intersecting two parallel lines are in the ratio 2:3, then the measure of the larger angle is

(a) 54°

(b) 120°

(c) 108°

(d) 136°

**Answer
10** :
In figure, l || m and p is transversal

= x 180° = 108° (c)

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