**ML Aggarwal CBSE Solutions Class 7 Math 9th Chapter Lines and Angles Exercise 9.1**

(1) (i) Can two right angles be complementary?

(ii) Can two right angles be supplementary?

(iii) Can two adjacent angles be complementary?

(iv) Can two adjacent angles be supplementary?

(v) Can two obtuse angles be adjacent?

(vi) Can an acute angle be adjacent to an obtuse angle?

(vii) Can two right angles form a linear pair?

**Solution: **

**(5) (i) Find the angle which is equal to its complement.**

**Solution:** Let the two equal angles be x and x

Then, x + x = 90 degree

=> 2x = 90 degree

=> x = 90 / 2

=> x = 45 degree

**(ii) Find the angle which is equal to its supplement.**

**Solution:** Let the equal angles be x.

Then, x + x = 180 degree

=> 2x = 180 degree

=> x = 180 / 2

=> x = 90 degree

**(6) Two Complementary angles are (x+4) ^{o} and (2x – 7)^{o}, find the value of x.**

**(7) Two supplementary angles are in the ratio of 2:7, find the angles.**

**(8) Among two supplementary angles, the measure of the longer angle is 44 ^{o} more than the measure of the smaller angle. Find their measures.**

**Solution: **

Therefore the smaller angle = 68 degree.

and longer angle = 68 degree + 44 degree = 112 degree.

**(9) If an angle is half of its complement, find the measure of angle.**

**(10) Two adjacent angles are in the ratio 5:3 and they together form an angle of 128 degree, find these angles.**

**Solution: **

**(13) In the adjoining figure, lines AB and CD intersect at F. If ∠EFA = ∠AFD and ∠CFB = 50 degree, find ∠EFC**

**Solution: **

it was really helpful but the 7th que done by u was partially done as you later have to multiply the answer with 2 and 7.

2X20+40 DEGREE

7X20=140 DEGREE!!!

It was really helpful

Actually I have a doubt in Question 8

Nice

In question no. 8 4 th point samajh nhi aya

Number bolo, we will understand you