Warm-up Session
Begin the lesson by conducting a simple activity to help students recall prior knowledge on congruency and triangles. Get a few paper cutouts of geometrical figures to the classroom. For example, you can get the cutouts of three triangles. Of these triangles, two triangles must be of the same shape and size, while one can be of a larger or a smaller size, but of the same shape. Now, ask the students to choose the congruent figures of the three. Thereafter, explain the concept of similarity with the help of the third triangle.
After studying this lesson, learners will be able to explain the concept of similarity. They will be able to prove the basic proportionality theorem and its converse, the AAA similarity criterion, the SSS similarity criterion and the SAS similarity criterion. Further, they will be able to prove  the Pythagoras Theorem  Additionally, the learners will be able to use the results obtained from the theorems and solve problems.