<PRE><B>Question 1181122</B>
the sum of the interior angles formula is:
S = 180 * (n - 2)
for a triangle, the sum is 180 * 1 = 180 degrees.
for a quadrilateral, the sum is 180 * 2 = 360 degrees.
if the sum is 900 degrees, then the formula becomes:
900 = 180 * (n - 2)
simplify to get 900 = 180 * n - 360
add 360 to both sides to get 1260 = 180 * n
divide both sides by 180 to get n = 1260 / 180 = 7
the number of sides = 7.
since the sum of the interior angles = 900, then each interior angle = 900 / 7 = 128.5714286 degrees.



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