Odpowiedzi

2010-04-07T16:20:09+02:00
H= 3 cm
a=x
b=x-5
P=1/2*(a+b)*h
P= 18cm kw.

18=1/2(x+x-5)*3
18=3x-7,5
3x=25,5
x=8,5

a=8,5
b=3,5
2010-04-07T16:25:22+02:00
H=3cm
a=b+5
p=18
p=1/2(a+b)*h
18=1/2(b+5+b)*3
18=1/2(2b+5)*3
18=b+2,5*3
18=3b+7,5
18-7,5=3b
3b=10,5 :3
b= 3,5
a=3,5+5=8,5
odp. dlugosci podstaw tego trapezu wynosza 8,5cm i 3,5 cm
2010-04-07T16:25:28+02:00
P= 1/2 a+b * h
18= 1/2 a + (a-5) * 3
18= 1/2 (a + a - 5) * 3
18 = 1/2 (2a - 5) *3
6 = 1/2 (2a - 5)
12 = 2a - 5
17 = 2a
a = 8,5 cm
b = a - 5 = 8,5 - 5 = 3,5 cm