Question

Calculando a área de um pentagono regular do lado 4 m, encontramos a área:

Answer 1

vamos usar a area do triangulo

A = b x h
.......____
...........2

b = 4

alpha = 360¤ / 5
alpha = 72¤
alpha = 36¤
____
.....2

tg 36¤ = (b/2)
................____
....................h

tg 36¤ = (4:2)
................____
....................h

h = (4/2)
......____
.......tg36¤

h = (4/2)
......____
......0,727

h =......2
......._____
.......0,727

h = 2,7624cm

h = 2,76cm


A area do triangulo b =4cm e h = 2,76cm

A = b x h
.......____
...........2

A = 4cm x 2,76
......._________
..............2


A = 11,04cm^2
.......____
............2

A = 5,52 cm^2


A area do pentagono e :

A = 5 x 5,52

A = 27,60 cm^2.

Resposta a area do tpentagono e 27,6cm^2...............