Area/perimeter of triangles

Madison was so enthused about learning about the area of triangles that she asked after lunch if she could spend the rest of the day writing a report/speech about the area of triangles. Who am I to say no? She's doing that now.

I loved the "click" moment she experienced today. It was when I gave her a triangle of base=3 height=3 and asked her the area ("Oh! It's 4-and-a-half"!). After that, a triangle with base 9 and height 7 was no problem. And everything else was easy.

Before I did triangles, I reviewed rectangle perimeter/area. (After she got that, I split one of the rectangles in half, into two triangles, and asked her what the area of the triangle must be.) Anyway, she was very pleased to figure out (with only me doing examples as guidance) that a 4 x 4 square was "the boundary" (her words) between when perimeter is bigger than area, and when area is bigger than perimeter.