The following is a list of the most commonly encountered shapes with pictures and names for each.
Triangles
editA list of different types of triangles, all of which have three sides and three angles.
Name | Definition | Picture | Seen in |
---|---|---|---|
Equilateral triangle | Three equal sides and three equal angles. | ||
Isosceles triangle | Two equal sides and two equal angles. | ||
Right triangle | One angle is a right angle (90 degrees or pi/2 radians) | Building construction | |
Scalene triangle | Not equilateral or isosceles |
Quadrilaterals
editA list of quadrilaterals, which have four sides and four angles.
Name | Definition | Picture | Seen in |
---|---|---|---|
Square | All four sides are equal length. All four angles are equal (90 degrees or pi/2 radians) | ||
Rectangle | All four angles are equal (90 degrees or pi/2 radians). Each pair of opposite sides are equal, i.e., if the sides are numbered clockwise: 1,2,3,4, then 1 & 3 would be equal and 2 & 4 would be equal. | Pieces of paper, doorways, most signs, etc. The most common shape in the modern world. |
Higher Polygons
editShapes with more sides than four.
Name | Definition | Picture | Seen in |
---|---|---|---|
Hexagon | Six sides and six angles | Pencil cross sections, honeycombs | |
Octagon | Eight sides and eight angles | Stop signs |
Curves
editShapes not made up of straight lines.
Name | Definition | Picture | Seen in |
---|---|---|---|
Circle | Perfectly round. All points same distance from center. | Coins, CDs, etc. | |
Oval |