Question

can anyone do 18 one please with method

Answer 1

Angle sum of octagon will be =(n-2)x180=(8-2)x180=6x180 degree 

as per given conditions two angles are 120 degree each and other six angles are equal . let six equal angle are X

six angle will be 6x

120+120+ 6 X =6x180

240+6X = 1080

6X=1080-240=840

X=840/6=140 degree 

answer 140 degree

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Answer 2

Let angles name be A =120

B = 120

C = x

D = x

E = x

F = x

H = x

Sum of all the interior angles of an Octagon is 1080

so on adding

x + x + x + x + x +x + 120 + 120 =1080

6x + 240 = 1080

6x =1080 - 240

6x =840

x =840/6

x =140

measurement of other six angles is

140 each