Visualizing how formulas came to be is no easy task, especially for students who struggle in math. It is important to accompany algebraic models with visual ones, in order to enhance understanding for all students. One area where this can implemented is explaining surface area formulas; incorporating nets is a great example of showing a visual (and even kinesthetic) representation of these concepts. One great example I have come across to visualize uses an orange peel to help show the relationship between area of circles, and surface areas of spheres.
Basically students measure the diameter of the orange, and draw four circles with the same diameter. Students then peel and flatten the orange peel and try to fit together the peel into as many circles as needed. Students will observe that the surface area of the orange is equal to the same amount as the area of the four circles that have the same diameter. This will help students to see how the two formulas are connected to each other! Plus they have the chance to get kinesthetic during class.
You can find this activity on the Math Solutions Webpage and searching for the activity "Orange You Glad...?" in the search bar. Happy teaching!