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CBSE NCERT Solutions for Class 7 Maths Chapter 5:
Identify which of the following pairs of angles are complementary and which are supplementary:
(i) 65º + 115º =180º.These are supplementary angles.
(ii) 63º + 27º =90º These are complementary angles.
(iii) 112º+ 68º =180º.These are supplementary angles
(iv) 130º+ 50º=180º.These are supplementary angles
(v) 45º+ 45º =90º These are complementary angles.
(vi)80º +10º =90º These are complementary angles.
An angle is greater than 45. Is this complementary angle greater than 45 or equal to 45 or less than 45?
Let the complementary angles be x and y ,i.e , x+y=90
It is given that x>45
Adding y both sides, x+y>45+y
Thus, its complementary angle is less than 45.
Fill in the blanks:
(i) If two angles are complementary, then the sum of their measures is ______________
(ii) If two angles are supplementary, then the sum of their measures is _______________
(iii) Two angles forming a linear pair are _______________
(iv) If two adjacent angles are supplementary, they form a _______________
(v) If two lines intersect at a point and if one pair of vertically opposite angles are acute angles, then the other pair of vertically opposite angles are_______________
(i) 90° (ii)1800 (iii)supplementary
(iv) Linear pair (v) equal (vi) obtuse angles
Find the angle which is equal to its complement:
Let one of the two equal complementary angles be x.
∴x+x=90 => 2x =90 =>x=90/2 =45º
Thus 45º is equal to its complement.
Find the angle which is equal to its supplement.
Let one of the two equal supplementary angles be x.
∴x+x=180 => 2x =190 =>x=180/2 =90º
Thus, 90 is equal to its supplement.