Question

usando equivalências das frações descubra o valor de x: a) 7/9=14/x<br />b) 4/7=x/28<br />c)7/2=x/12<br />d)15/30=x/2<br />e)3/11=9/x<br />f)1/8=x/40<br />g)6/18=1/x<br />h)40/12=10/x

Answer 1

Pra se constatar equivalência basta fazer os meios pelos extremos, ou seja multiplicação cruzada.


a) 7/9=14/x
7.x=14.9
7x=126
x=126/7
x=18


b) 4/7=x/28
7.x=28.4
x=112/7
x=16


c)7/2=x/12
2.x=12.7
x=84/2
x=42

d)15/30=x/2
30.x=15.2
x=30/30
x=1


e)3/11=9/x
3.x=11.9
x=99/3
x=33


f)1/8=x/40
8.x=40.1
8x=40
x=40/8
x=5

g)6/18=1/x
6.x=18.1
x=18/6
x=3

h)40/12=10/x
40.x=12.10
x=120/40
x=3