Abstract
The variety and richness of geometric problems in the field of measure is very often limited to simply substituting into unexplored patterns. The paper presents several stimulating tasks arising from a teaching experiment carried out during six lessons in two classes of the 7th grade at elementary school in Prague.
Teaching was focused on students' activities and was planned so that the individual activities were as diverse and motivating as possible, and especially so that the student has the opportunity to explore a sufficient number of isolated models to find a relationship for calculating the area of triangle and parallelogram.