Given the formula A =pieab solve for a.

a = A/πb

Step-by-step explanation:

To solve this subject of the formulae given that A = πab.

solution

A = πab

the next step is to look for a unique way to get rid of the variables disturbing "a" from standing alone. this variables are π and b, we need to detach dem from a

A = πab

divide both sides by πb

A/πb = πab/πb

A/πb = a

a = A/πb

therefore  the value of a in the fomular A = πab is evaluated to be  a = A/πb

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional