GMAT Quant Questions | Geometry #6

This GMAT quant practice question is a problem solving question in Geometry. Concept: Finding number of diagonals of an n-sided convex polygon.

Question 6: How many diagonals does a 63-sided convex polygon have?

1. 3780
2. 1890
3. 3843
4. 3906
5. 1953

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Video Explanation

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Explanatory Answer | GMAT Geometry

Number of diagonals in a polygon

The number of diagonals of an n-sided convex polygon = \\frac{\text{n(n - 3)}}{\text{2}})
This polygon has 63 sides. Hence, n = 63.
Therefore, number of diagonals = \\frac{\text{63 × 60}}{\text{2}}) = 1890.

Choice B is the correct answer.