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SAI InternationalSchool
CLASS - IX

Mathematics
CHAPTER-6: LINES AND ANGLES-1

Assessment (Subjective)-1ANSWERS

SUBTOPIC:Basic Terms and definitions

1.
Find the complement of of a right angle.

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Solution:We know that of a right angle can be written as × 90 = 60

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Complement60 =90 – 60 = 30
2.
Find the supplement of of a right angle.

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Solution:We know that of a right angle can be written as × 90 = 54

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Supplement of 54 = 180 – 54 = 126 .
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3. Find the measure of an angle which is 36 more than its complement.
Solution:Consider the required angle as x 0
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We know that the complement can be written as 90 – x
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x = (90 – x + 36
x + x = 90 + 36
2x = 126
x = 126/2
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x = 63
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Therefore, the measure of an angle which is 36 more than its complement is 63 .
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4. Find the value of x for which the angles (2x – 5) and (x – 10) are the
complementary angles.
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Solution:It is given that (2x – 5) and (x – 10 are the complementary angles.
So, we can write it as
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(2x – 5) + (x – 10) = 90
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