Question

Which polygon has interior angles whose sum is 1440°? octagon nonagon decagon 11-gon

Answer 1

Answer:

decagon

Step-by-step explanation:

1440=180(n-2)

8=n-n

n=10  

this means that your answer is going to is decagon.

Answer 2

Answer:

Decagon

Step-by-step explanation:

We can use the general equation to determine the sum of interior angles:

$I.A. = 180 \times (n-2)$

Since we know the sum of interior angles (I.A.) is 1440°, we must figure out n - the number of sides and so:

$1440=180(n-2)\\\\\frac{1440}{180}=n-2\\\\8=n-2\\\\n=10$

Since n=10 this means that it is a 10 sided shape meaning it's a decagon.