Distance, Area, Volume Unit Study - Area of Triangles

Day 8: Area of Triangles
The kids developed a method for determining the area of triangles.

Previously, the kids learned to figure the area of right isosceles triangles by drawing squares and triangles, but today, the triangles were not right isosceles, so the method didn't work.

The formula for the area of a triangle is 1/2 the area of a rectangle with the same base and height as the triangle, but explaining that to my son caused confusion. Therefore, I gave him an isosceles triangle cut into two pieces. He rearranged the pieces so that they fit together in a rectangle as shown above. From the rectangle he was able to determine the area.

Next he was given only one of the triangles shown above and some time to think. He determined that the area was 1/2 the rectangle's area.

My seven year old was able to complete this and all of our other distance, area, volume activities as well.

Figures are abstract as compared with manipulatives which are concrete. Making the transition into abstract figures which represent objects can be very difficult for some children, including my son. Therefore, sketches on paper were created to review what the kids discovered and get them used to seeing sketches.