Answer:
1440 degrees.
Step-by-step explanation:
125 + 140 + 160 = 425 degrees.
The remaining angles are each 145.
The exterior angles of all polygons sum to 360 .
So we have exterior angles sum of the 3 given angles
= (180-125) + ( 180-140) + (180-160)
= 55 + 40 + 20 = 115.
So the remaining vale of the sum is 360 - 115
= 245 degrees.
An internal angle of 145 will give an external one of 35 degrees.
245/35 = 7.
So there are 7 145 degree angles in the polygon.
Sum of the interior angles is therefore:
425 + 7*145
= 1440 degrees.
This is a 10 sides polygon ( a decagon).
