Sorting Obtuse Triangles by Area

Have you ever noticed that triangles can look completely different yet share the same name? Sorting Obtuse Triangles by Area helps you take a closer look at triangles with one angle greater than 90 degrees and compare them in a meaningful way. In this playsheet, you’ll calculate the area of different obtuse triangles and then sort them from smallest to largest. You’ll discover that math is not only about getting the right answer—it’s about understanding how shapes relate to one another.

As you begin, you’ll learn how to apply the triangle area formula—½ × base × height—to each triangle. You’ll also explore how the height in an obtuse triangle is sometimes located outside the shape, requiring you to extend a line to see it clearly. These steps help you understand why geometry demands careful attention and logical thinking. The more you work with obtuse triangles, the easier it becomes to spot what information you need. Soon, identifying and calculating areas turns into a skill you can trust.

This playsheet encourages you to compare the triangles after finding their areas. You’ll list them in order, identify the largest and smallest, and explain how the measurements contributed to those differences. These tasks help you understand that area is not based only on how a triangle looks—but on the relationship between its base and height. You begin to recognize that two triangles can appear similar but still have very different areas.