# RS Aggarwal Solutions Class 9 Mathematics Solutions for Lines And Angles Exercise 7A in Chapter 7 - Lines And Angles

Question 3 Lines And Angles Exercise 7A

Find the supplement of each of the following angles:

(i) 42

(ii) 90

(iii) 124

(iv) 3/5 of a right angle

(i) We know that the supplement of 42 can be written as

42 = 180 - 42 = 138

(ii) We know that the supplement of 90 can be written as

90 = 180 - 90 = 90

(iii) We know that the supplement of 124 can be written as

124 = 180 - 124 = 56

(v) We know that 3/5 of a right angle can be written as 3/5 × 90 = 54

54 = 180 - 54 = 126

Video transcript
"hello students welcome to linux q and a video session i'm saf your math tutor and question for today is find the supplement of each of the following angles now here the angles are given the first one is 42 okay so first one here we'll find the first one supplement of 42 so the first one yeah four angles are given the first one is supplement of 42 here we'll do second third and fourth fine continuing here with 42 have to find the supplement now we know that supplement can be written as 180 minus 42 so supplement of any angle is 180 minus angle that angle okay so here as per this we can write supplement of 42 is 180 minus 42 so it is 180 minus 42 is equal to 138 this is the supplement of 42. the second one is 90. so supplement we have to find the supplement of 90 degree here also degree supplement of 90 degree can be written as 180 minus 90 so here 180 minus 90 degree will be equal to 90 degree hence supplement of 90 degree is 90 the third one is 124 degree so here 124 degree solving this you know that the supplement of 124 degree is 180 minus 124 and that is 180 minus 124 will be equal to 56 degree right so here we have supplement of 124 degree is 56 degrees fine the fourth one the fourth one is three by five of a right angle three by five of a right angle so this is the question for us now three by five of a right angle three by five off means it is a keyword its sign is multiply so three by five of right angle right angle is 90 degree will be equal to how to see t by pi of 90 degree will be equal to 54 you can simplify it and you will get 54 so 54 here now we have to find three by five of right angle its supplement now the supplement of 54 we have to find we already know that supplement of 54 is 180 minus 54. hence 180 minus 54 is equal to 126 so these are the one answers for each of the supplements asked the answers are 138 degree for 42 degree 90 degree for 90 degree 156 degree for 124 degree and three by five of our right angle supplement is 126 degree that is our answer if you have any doubts you can drop it down it in our comment section and subscribe to our channel for more such interesting questions thank you for watching "
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