What is the sum of the measures of the interior angles of a polygon QRST A.)180
B.)360
C.)90
D.)720

B

Step-by-step explanation:

The sum of the interior angles of a polygon is given by the formula s=180(n-2), where s is the sum and n is the number of sides.

In this case, the polygon has 4 sides, so we can sub n for 4.

This gives s=180(4-2) or s=180×2.

Solving this gives the result of s=360.

**This question involves interior angles of polygons, which you may wish to revise. I'm always happy to help!

B)  360°

Step-by-step explanation:

use the formula (n-2)·180° where 'n' is the number of sides the polygon has

the sum of the interior angles in a quadrilateral will always have 360°;

(4-2)180 = 2(180) = 360

Step-by-step explanation:

a + c = 321

6a + 4c = 1590

c = 321 - a

6a + 1284 - 4a = 1590

2a = 306

a = 153

c = 168