The sum of the interior angles of a polygon is 1260∘. how many sides does the polygon have?

140 degrees.

Step-by-step explanation:

All sides are the same length (congruent) and all interior angles are the same size (congruent). To find the measure of the angles, we know that the sum of all the angles is 1260 degrees (from above)... And there are nine angles... So, the measure of the angle of a regular nonagon is 140 degrees.

Source: www.coolmath.com%2Freference%2Fpolygons-09-nonagons&usg=AOvVaw2hnOO2u2ydxnY6u5Yu1Qol

21 sides

Step-by-step explanation:

I don't know the right, but this is an alternative solution you can use also. Since a triangle's angles add up to 180, I kept multiplying 180. 180x7=1260. And 7x3=21 because a triangle has 3 angles

a.

step-by-step explanation:

step 1 distribute 2 to every term in the parentheses

step 2 add 10 on both sides of the equal sign

1. minimum

2. 6400

3. eight

hope this !