It shows how to figure out the areas of all kinds of triangles. Since the steps are listed in order, you can write them down in a notebook and then try to do them on your own. The only way to get better grades in math is to study in a planned and organised way, and practising Triangles from this book will help you do that. Be consistent with your habits, because that's what you need to do. This book is one of the best ones you can get to help you understand the Chapter.