Posted by Katie on Wednesday, March 23, 2011 at 6:09pm.
what is the length of any diagonal of a regular pentagon with a side of 20mm ?

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

geometry  Reiny, Wednesday, March 23, 2011 at 7:24pm
first find the size of each interior angle
angle = 180(52)/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  A regular pentagon has side length 12cm.the perimeter of the pentagon...
 geometry  a regular pentagon has an apothem of 3.2 and an area of 37.2 cm. What...
 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...
More Related Questions