Nombre
Área interior
Perímetro
Lados
Vértices
Comentarios
Dibujo
Triángulo
b
h
2
{\displaystyle {\frac {bh}{2}}}
a
+
b
+
c
{\displaystyle a+b+c\,}
3
{\displaystyle 3\,}
3
{\displaystyle 3\,}
b base , h altura , a c Triángulo
Triángulo equilátero
3
4
a
2
{\displaystyle {\frac {\sqrt {3}}{4}}a^{2}}
3
a
{\displaystyle 3a}
3
{\displaystyle 3\,}
3
{\displaystyle 3\,}
a
Cuadrado
a
2
{\displaystyle a^{2}\,}
4
a
{\displaystyle 4a}
4
{\displaystyle 4\,}
4
{\displaystyle 4\,}
a Cuadrados
Rombo
A
C
¯
⋅
B
D
¯
2
{\displaystyle {\frac {{\overline {AC}}\cdot {\overline {BD}}}{2}}}
4
a
{\displaystyle 4a\,}
4
{\displaystyle 4\,}
4
{\displaystyle 4\,}
a AC diagonal menor, y BD diagonal mayor
Rombo
Rectángulo
b
h
{\displaystyle bh}
2
(
b
+
h
)
{\displaystyle 2(b+h)}
4
{\displaystyle 4\,}
4
{\displaystyle 4\,}
b h altura
Paralelogramo
b
h
{\displaystyle bh}
2
(
a
+
b
)
{\displaystyle 2(a+b)}
4
{\displaystyle 4\,}
4
{\displaystyle 4\,}
b a h altura
Paralelogramo
Trapecio
(
a
+
c
)
h
2
{\displaystyle {\frac {(a+c)h}{2}}}
a
+
b
+
c
+
d
{\displaystyle \ a+b+c+d\,}
4
{\displaystyle 4\,}
4
{\displaystyle 4\,}
a c h altura , b d
Pentágono regular
25
+
10
5
4
a
2
{\displaystyle {\frac {\sqrt {25+10{\sqrt {5}}}}{4}}a^{2}}
5
a
{\displaystyle 5a}
5
{\displaystyle 5\,}
5
{\displaystyle 5\,}
a
Polígono regular
n
a
b
2
{\displaystyle {\frac {nab}{2}}}
n
⋅
a
{\displaystyle n\cdot a}
n
{\displaystyle n\,}
n
{\displaystyle n\,}
a b apotema del polígono, y n
Polígono regular
n
2
sen
(
2
π
n
)
r
2
{\displaystyle {\frac {n}{2}}\operatorname {sen} \left({\frac {2\pi }{n}}\right)r^{2}}
n
⋅
a
{\displaystyle n\cdot a}
n
{\displaystyle n\,}
n
{\displaystyle n\,}
a r n radianes .
![{\displaystyle P\approx \pi \left[3(r_{1}+r_{2})-{\sqrt {(3r_{1}+r_{2})(r_{1}+3r_{2})}}\right]\!\,}](https://wikimedia.org/api/rest_v1/media/math/render/svg/06624521359bef81b9e8fb14a73f385e69adc4ef)
