the measure of the seven angles in a nonagon measure 138 154 145 132 128 147 and 130. if the two remaining angles are equal in measure, what is the angle of each measure?

Question

i need help i don't know what i'm supposed to do on this question because i wasn't here when my teacher taught it.

Answer 1

The sum of the interior angles of a polygon are (n-2)*180, where n is the number of sides. So the sum of the interior angles of a nonagon where n = 9 is (9-2)*180 = 1260.

The sum of the given 7 interior angles is 974, leaving 1260 - 974 = 286 for the remaining two equal angles.'

Thus each of those angles must measure 286/2 = 143.

Answer 2

A nonagon is 9 angles. To find the total angles in this, it would be (n-2)*180 where n is the number of angles.

(9-2)*180 = 1260

Now, we need to see what the total number is without the 2 remaining angles.

138+154+145+132+128+147+130 = 974

1260-974 = 286 angles remaining. Since both are the same size

286/2 = 143 degrees