Question

Which polygon has an interior angle sum of 900°?

A polygon has 8 sides.
A polygon has 10 sides.
A polygon has 9 sides.
A polygon has 7 sides.

Answer 1

To find the polygon that has an interior angle sum of 900°, we can use the formula for the interior angle sum of a polygon, which is given by \( S = (n - 2) \times 180° \), where \( n \) is the number of sides.

We can calculate the interior angle sum for polygons with different numbers of sides:

1. For a polygon with 7 sides (\( n = 7 \)):
\[
S = (7 - 2) \times 180° = 5 \times 180° = 900°.
\]

2. For a polygon with 8 sides (\( n = 8 \)):
\[
S = (8 - 2) \times 180° = 6 \times 180° = 1080°.
\]

3. For a polygon with 9 sides (\( n = 9 \)):
\[
S = (9 - 2) \times 180° = 7 \times 180° = 1260°.
\]

4. For a polygon with 10 sides (\( n = 10 \)):
\[
S = (10 - 2) \times 180° = 8 \times 180° = 1440°.
\]

From these calculations, we can see that the polygon with 7 sides has an interior angle sum of 900°.

Therefore, the answer is:
**A polygon has 7 sides.**