(1) He calculates the side of a regular pentagon in terms of the radius of the circumscribed circle.

(2) This says that the most stable arrangement is a pentagon surrounded by five hexagons.

(3) You may know about a pentagon , a hexagon, or an octagon.

(4) Write the number 1 through 10 in the boxes below so each side of the pentagon has a sum of 14.

(5) When I looked at what she was doing, she was trying to work out (on the napkin) how to calculate the sum of the internal angles of a pentagon .

(6) Although it is impossible to inscribe a regular pentagon in a square, an equilateral pentagon can be inscribed in two ways.

(7) In the second case, if the convex polygon is a pentagon incorporating all five points, then any four of these points can be connected to form a quadrilateral.

(8) Similarly, nine atoms can form a pentagon bonded to a hexagon, each ring sharing two atoms with the other ring.

(9) There are 24 ways to do it - make 12 pentagons, so that the mirror images are on each side of the pentagon .

(10) Thus, you can readily obtain a curved pentagon , heptagon, and so on.

(11) They are marked by a pentagon with three overlapping triangles.

(12) Perfect crystal structures can contain pyramids, cubes, or hexagons, but not pentagons .

(13) Analysts also use a variety of symbols, such as parallelograms, pentagons , and others, to depict different types of events and activities.

(14) Here are two pictures of the pentagonal coffee table that I mentioned in the book.

(15) Of course, this statement has to be explained, since it is untrue if we understand distance in the usual way: the edges of these pentagons are visibly not straight and do not have the same length.

(16) They are formed from 60 atoms of carbon bonded together in a combination of pentagons and hexagons to form a ball, just like a soccer ball.

(17) The hexagons, pentagons , and triangles that make up the biomes all have their own unique specification due to the irregular nature of the site.

(18) For those who don't know, a buckyball is an extremely stable soccer-ball-shaped molecule made up of 20 hexagons and 12 pentagons .

(19) Father entered the room, arms full of suitcases shaped in rectangles, pentagons , squares, and even spheres.

(20) In plan, the building is comprised of five concentric pentagons , known as rings.