Question

Two angles of a

Answer 1

Answer:

$5\ sides$

Step-by-step explanation:

we know that

The formula to calculate the sum of the interior angles in a polygon is equal to

$S=(n-2)180^o$ ----> equation A

where

n is the number of sides of the polygon

In this problem we have that the sum is equal to

$S=2(90^o)+(n-2)120^o$ ---> equation B

Equate equation A and equation B

$(n-2)180^o=2(90^o)+(n-2)120^o$

solve for n            

Applying distributive property both sides

$180n-360=180+120n-240$

Group terms

$180n-120n=180-240+360$

Combine like terms

$60n=300$

Divide by 60 both sides

$n=5\ sides$