Alright, lets get started.
If the polygon measures 45 degree exterior angle and we are asked to find number of sides, there is a formula for that.
= value of exterior angle
Where n is number of sides of ploygon
Multiplying n into both sides
Now divide 45 in both sides
n = 8
Means number of sides of polygon is 8, hence its Octagon. Answer
Now we have given 45 exterior angle hence interior angle would be
180 - 45 = 135°
So, sum of all interior angles would be = number of sides * interior angle
sum of all interior angles would be =
Hence sum of all interior angles would be 1080°. Answer
Hope it will help :)