(a) The sum of Interior angles of n-sided polygon = (n-2)x 180

3 x 150 =450

so the rest of angles are 135 are (n-3)

Hence,

(n-2) x 180 = 450 + (n-3) x 135

n = 9

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(b)The sum of exterior angles of n-sided polygon = 180(n+2)

Hence,

the sum of exterior angles of hexagon = 180 x 8 = 1440

the sum of exterior angles of triangle = 180 x 5 = 900

the sum of exterior angles of hexagon + the sum of exterior angles of triangle

= a + b + c + d + e + f + g + h + i – 360

= 1440 + 900 – 360

= 1980