3420°
explanation:
the equation of the sum of interior angles are (n-2)x180
polygon above has 21 sides so you sub n as 21 and plug the equation in the calculator
Answer: 3420
Step-by-step explanation: To find the sum of interior angles of a polygon, multiply the number of triangles in the polygon by 180°.
Therefore the formula is (n-2)×180, n being the number of sides. Therefore it's (21-2)×180 which gives you 3420.
