How_To_Be_Good_At_Math

214 GEOMETRY • TRIANGLES

Triangles

A triangle is a type of polygon. It has three sides,

three vertices, and three angles.

Congruent triangles

Two or more triangles that have sides

the same length and angles the same

size are called congruent triangles.

These triangles face different directions

but are still congruent.

In geometry, we give special names

to different parts of a triangle.

The base is at

the bottom

All the triangles are the

same size and shape

Parts of a triangle

Side

The three straight lines

that make up the triangle

are called sides.

Vertex

A corner of a

triangle, where two

lines meet, is a

vertex. The word for

more than one

vertex is vertices.

Base and apex

The base is the side

that the triangle “rests”

on. The apex is the vertex

at the top of the triangle,

opposite the base.

A triangle is a polygon

with three straight sides

and three angles.

Apex

214_215_Triangles.indd 214 29/02/2016 18:04