Friday

February 27, 2015

February 27, 2015

Posted by **Katie** on Wednesday, March 23, 2011 at 6:09pm.

- Geometry quick i have test tomorrow -
**Katie**, Wednesday, March 23, 2011 at 7:15pmwhat is the length of any diagonal of a regular pentagon with a side of 20mm

- geometry -
**Reiny**, Wednesday, March 23, 2011 at 7:24pmfirst find the size of each interior angle

angle = 180(5-2)/5 = 108°

let the length of the diagonal be x

by cosine law

x^2 = 20^2 + 20^2 -2(20)(20)cos 108°

I am sure you can finish it from there.

**Answer this Question**

**Related Questions**

Geometry - what is the length of any diagonal of a regular pentagon with a side ...

Geometry - Hi, I'm having a difficult time understanding a couple of Geometry ...

Geometry - The perimeter of a regular pentagon is 31 cm. Find the length of each...

Geometry - If a regular pentagon has sides of four feet, what is the length from...

Geometry - If each side of a regular pentagon is x^2 + 17 and each side of a ...

geometry - the lengths [in inches] of two sides of a regular pentagon are ...

pentagon...GEOMETRY - ABCDE is a regular pentagon. FAD is an equilateral ...

Geometry - What is the area of a regular pentagon with a side length of 9.4 feet...

Geometry help - A parallelogram has a 7-inch side and a 9-inch side, and the ...

Math Geometry - there are 2 pentagons the small pentagon has a side that is 3cm ...