Answer:
- 10 sides
- angles total 1440°
Step-by-step explanation:
The formula for the total of interior angles can be used together with the given angle values to write an equation for the number of sides.
<h3>Setup</h3>
The total of interior angles of an n-sided polygon is 180°×(n -2). In the given n-sided polygon, two angles are 120° and (n -2) angles are 150°. The total of angles is the same either way it is computed:
2×120 +(n -2)150 = (n -2)180
<h3>Solution</h3>
Subtracting (n-2)150, we have ...
240 = 30(n -2)
8 = n -2 . . . . . . . . divide by 30
10 = n . . . . . . . . add 2
The polygon has 10 sides.
The total of interior angles is ...
angle sum = 180°×(10 -2) = 1440°
The sum of interior angles is 1440°.