Dear Student, Sum of interior angles of regular polygon is n-2×180°Sum of angles = 2×90°+n-2×120°So, n-2×180°=2×90°+n-2×120°180n-360=180+120n-240180n-120n=-60+36060n=300n=30060 = 5Hence, the number of sides in the polygon is 5 Regards

11 one pls

11 one pls c B (ii) Write the value of ZA + ZE. (iii) Find angles B, C and D. 11. Two angles of a polygon are right angles and he remaining are 1200 each. Find the number of Sides in it. 12. in a hexagon ABCDEF, side AB is parallel to FE and LB : : : : 3. find LB and LD. 13. The anglesofa hexagon are x + 100, 2x +200, Findx 14. In a pentagon, two angles are 400 and 600 and the rest are in the ratio 1 : 3 : 7. Find biggest angle of the pentagon.

Dear Student,

S u m o f i n t e r i o r a n g l e s o f r e g u l a r p o l y g o n i s (n - 2) \times 180 ° S u m o f a n g l e s = 2 \times 90 ° + (n - 2) \times 120 ° S o, (n - 2) \times 180 ° = 2 \times 90 ° + (n - 2) \times 120 ° 180 n - 360 = 180 + 120 n - 240 180 n - 120 n = - 60 + 360 60 n = 300 n = \frac{300}{60} = 5 H e n c e, t h e n u m b e r o f s i d e s i n t h e p o l y g o n i s 5 .

Regards

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