Answer:
10cm
Step-by-step explanation:
First let's define variables a and x:
a = area of rectangle and square
x = side of square
Now let's create an equation to calculate a using the square and an equation to calculate a using the rectangle:
Using square:
Using rectangle:
Now we want to solve for x so let's combine the equations since they are both equivalent to a
Simplify
Solving this we get 10 and -3
Since it is impossible for a square to have a negative side value we can conclude that the value is 10cm
This can then be checked by plugging in 10 as x in our equations and seeing if we get the same a value:
Using square:
Using rectangle: