ICSE-VIII-Mathematics
16: Understanding Shapes (Including Polygons) Class 8 Maths
- #1Fill in the blanks :
In case of regular polygon, with :
Ans :
Explanation
i) Each exterior angle = 360Ëš/8 = 45Ëš
Each interior angle = 180Ëš - 45Ëš = 135Ëš
(ii) Each exterior angle = 360Ëš/12 = 30Ëš
Each interior angle = 180Ëš - 30Ëš = 150Ëš
(iii) Since each exterior = 72Ëš
∴ Number of sides = 360˚/72˚ = 5
Also interior angle = 180Ëš - 72Ëš = 108Ëš
(iv) Since each exterior angle = 45Ëš
∴ Number of sides = 360˚/45˚ = 8
Interior angle = 180Ëš - 45Ëš = 135Ëš
(v) Since interior angle = 150Ëš
∴ Exterior angle = 180˚ - 150˚ = 30˚
∴ Number of sides = 360˚/30˚ = 12
(vi) Since interior angle = 140Ëš
∴ Exterior angle = 180˚ - 140˚ = 40˚
∴ Number of sides = 360˚/40˚ = 9