Respuesta :

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.