What’s the indicated measure

We know that the interior angles of the polygon is 360 degrees, given to us by the formula [tex] 180(n - 2) [/tex], where [tex] n [/tex] is the number of sides of the shape.
Thus, all interior angles must sum to 360 degrees. By this we can calculate [tex] n [/tex]:
[tex] 4n + (5n + 6) + (8n - 12) + (9n + 2) = 360 [/tex]
Combining like terms, we find:
[tex] 26n - 4 = 360 [/tex]
[tex] 26n = 364 [/tex]
[tex] \boxed{n = 14} [/tex]
Our answer is n = 14.
<A + <B + <C + <D = 360
where
<A = 4n
<B = 9n + 2
<C = 8n - 12
<D = 5n + 6
So
4n + 9n + 2 + 8n - 12 + 5n + 6 = 360
combine like terms
26n - 4 = 360
Add 4 to both sides
26n = 364
Divide both sides by 26
n = 14
Substitute n = 14 into those below to find measure of each:
<A = 4n = 4 *14 = 56
<B = 9n + 2 = 9*14 + 2 = 128
<C = 8n - 12 = 8*14 - 12 = 100
<D = 5n + 6 = 5*14 + 6 = 76
Answer:
n = 14<A = 56°
<B = 128°
<C = 100°
<D = 76°