# PSAT Math : How to find the length of a side of a polygon

## Example Questions

### Example Question #1 : Other Polygons

If the following shape was going to be drawn in a circle, what is the minimum radius of the circle?

11

8

7

9

10

7

Explanation:

IF you draw the longest diagonal across the shape, the length of it is 13.4. This means the radius must be at least 6.7. The answer is 7.

### Example Question #1 : How To Find The Length Of A Side Of A Polygon

Note: Figure NOT drawn to scale.

The above polygon has perimeter 190. Evaluate .

Explanation:

To get the expression equivalent to the perimeter, add the lengths of the sides:

Since the perimeter is 190, we can simplify this to

and solve as follows:

### Example Question #2 : How To Find The Length Of A Side Of A Polygon

Note: Figure NOT drawn to scale.

The perimeter of the above polygon is 225. Also, .

Evaluate .

Insufficient information exists to answer the question.

Explanation:

To get the expression equivalent to the perimeter, add the lengths of the sides:

Since the perimeter is 225, we can simplify this to

and, furthermore, since ,