Extending a (TIMSS) Japanese Lesson Using Trigonometry
David Pagni, Harris Shultz
March 1999, Volume 92, Issue 3, Page 189
One of the Japanese mathematics lessons reported in the Third International Mathematics and Science Study (TIMSS) involves the concept of the area of a triangle. On the first day, students explore the area of triangles obtained by using the same base but translating the vertex opposite the base along a path parallel to the base, thus keeping the height constant. The next day the students are reminded of that property and are given a challenging problem that applies the property.