Question

Quanto vale X em cada caso:
$\frac{3}{4} = \frac{15}{ \times }$
$\frac{5}{ \times } = \frac{35}{21}$
$\frac{ \times }{18} = \frac{3}{2}$

Answer 1

Nesses casos basta multiplicar em cruz.

a)

3/4 = 15/x

3.x = 4.15

3x = 60

x = 60/3

x = 20

b)

5/x = 35/21

5.21 = x.35

105 = 35x

x = 105/35

x = 3

c)

x/18 = 3/2

x.2 = 18.3

2x = 54

x = 54/2

x = 27