Answer:
concrete operational stage
Step-by-step explanation:
Have a look at the attached photo below, it may be your full question:
The concrete operational stage is the third phase in Piaget's cognitive development theory. This period spans the period between childhood, it begins around 7 years of age and continues until about 11 years of age and is characterized by the development of logical thinking.
Lets say we have a rectangle. if the ratio is 7:5, we can put the width as 7x, and the length as 5x (or vice versa, it doesn't really matter.) If the perimeter is solved by 2(h+w), we have 2(7x+5x)=96, or 2(7x)+2(5x)=96, which is C
X=2 because first you have to combine like terms. Than you have to bring the Varible on one side. Finally you solve for the Varible and you get the answer2.
169=13
144=12
Hope this helps and please give brainliest!