A/40 = 3/10 solve the proportion.

a =12

Since

a

b

=

c

d

,

we can use an algebraic technique, to get the value of

a

, by isolation and using the golden rule of algebra, "Balancing the equation"

a

40

=

3

10

to isolate

a

, we must eliminate

40

in the left side of the equation by multiplying it by

40

, the golden rule of algebra states that whatever you do in a side of an equation is you also must do it in the other side to keep the equation balanced.

(

40

)

a

40

=

3

10

(

40

)

40

a

40

=

(

40

)

(

3

)

10

a

=

120

10

, we can still simplify the answer giving,

hi, i am not sure about this one but i think its d,

hope this !

it could 14.28 but if its not that one then it has to be the 17 one. hope this ! : )

step-by-step explanation: