The formula to find the measure of an interior angle is

, where

represents the number of sides in the polygon. In this problem,

would represent

.
Let's plug in the value for


Let's simplify that.

Now we know that the <span>measure of an interior angle of a regular three-sided polygon is 60</span>°.
Your answer would be B!Let me know if you have any questions regarding this problem!
Thanks!
-TetraFish
Answer:
the last one
Step-by-step explanation:
Answer:
45x happy to help ya :)
Step-by-step explanation:
First step find a common multiple, e.g. 45 and subtract
9x + 5y = 28 * 5
5x + 9y = 56 * 9
45x + 25y = 140
-(45x + 81y = 504)
-56y = -364
56y = 364
y = 6.5
Substitute into any equation
9x + 5(6.5) = 28
9x + 32.5 = 28
9x = -4.5
x = -0.5
x = -0.5 , y = 6.5