Objective
By the end of this lesson, you will be able to identify and describe different types of triangles.
Materials and Prep
- Pencil
- Blank paper
No prior knowledge is required for this lesson.
Activities
- Start by drawing a large triangle on your paper.
- Label the three sides of the triangle as A, B, and C.
- Measure the lengths of each side using a ruler and record the measurements next to the corresponding labels.
- Now, examine the angles of the triangle. Measure and record the measures of each angle.
- Based on the lengths of the sides and the measures of the angles, determine the type of triangle you have drawn. Is it equilateral, isosceles, or scalene? Is it acute, obtuse, or right?
- Repeat this activity with at least two more triangles of your own creation.
Fifth Grade Talking Points
- "Triangles are polygons with three sides and three angles."
- "An equilateral triangle has three equal sides and three equal angles. Each angle measures 60 degrees."
- "An isosceles triangle has two equal sides and two equal angles. The angles opposite the equal sides have the same measure."
- "A scalene triangle has no equal sides and no equal angles."
- "An acute triangle has three acute angles, meaning all angles are less than 90 degrees."
- "An obtuse triangle has one obtuse angle, meaning one angle is greater than 90 degrees."
- "A right triangle has one right angle, meaning one angle measures exactly 90 degrees."