This lesson plan is for a 9th grade mathematics class on geometry and measurement. The topic is on identifying properties of similar and congruent triangles. Students will learn about congruency by determining if figures are congruent, identifying proportions of sides in congruent triangles, and listing properties and requirements of congruent triangles. They will also prove triangles are congruent and distinguish between similarity and congruency. The lesson will involve the teacher explaining concepts, providing examples and non-examples, testing student understanding, and having students integrate and summarize their learning.