ANSWER:

3240 degrees

Step-by-step explanation:

Sum of the Interior Angles

Sum of interior angles is 180° (n - 2). The way I remember this equation is by remembering that the equation contains 180° and the number of sides, and that the sum of interior angles of a triangle is 180°.

180° (18 - 2)

180° (16)

(200 - 20)° (16)

(3200 - 320)°

2880°

Can also find the sum by multiplying I by n

160° * 18

160° * (20 - 2)

3200° - 320°

2880°

Sum of the Interior angles

360° + 2880° = 3240°