## Example Questions

### Example Question #1 : How To Find The Length Of The Diagonal Of A Hexagon

How many diagonals are there in a regular hexagon?      Explanation:

A diagonal is a line segment joining two non-adjacent vertices of a polygon.  A regular hexagon has six sides and six vertices.  One vertex has three diagonals, so a hexagon would have three diagonals times six vertices, or 18 diagonals.  Divide this number by 2 to account for duplicate diagonals between two vertices. The formula for the number of vertices in a polygon is: where .

### Example Question #3 : How To Find The Length Of The Diagonal Of A Hexagon

How many diagonals are there in a regular hexagon?

10

9

6

3

18

9

Explanation:

A diagonal connects two non-consecutive vertices of a polygon.  A hexagon has six sides.  There are 3 diagonals from a single vertex, and there are 6 vertices on a hexagon, which suggests there would be 18 diagonals in a hexagon.  However, we must divide by two as half of the diagonals are common to the same vertices. Thus there are 9 unique diagonals in a hexagon. The formula for the number of diagonals of a polygon is: where n = the number of sides in the polygon.

Thus a pentagon thas 5 diagonals.  An octagon has 20 diagonals.

### Example Question #3 : Hexagons

Hexagon is a regular hexagon with sides of length 10. is the midpoint of . To the nearest tenth, give the length of the segment .      Explanation:

Below is the referenced hexagon, with some additional segments constructed. Note that the segments and have been constructed. Along with , they form right triangle with hypotenuse . is the midpoint of , so . has been divided by drawing the perpendicular from to the segment and calling the point of intersection . is a 30-60-90 triangle with hypotenuse , short leg , and long leg , so by the 30-60-90 Triangle Theorem, and For the same reason, , so By the Pythagorean Theorem,     when rounded to the nearest tenth.

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