Third-grade students need plenty of hands-on activities to help them visualize and learn math concepts. Showing students a geometrical shape can add context to a lesson on area. Teachers should aim to teach students how to work with shapes and recognize a shape's attributes. Students should learn how to break up shapes into smaller parts to master the concepts and skills she needs to calculate the area of an object. At the third-grade level, students should develop an understanding of the concept of area with the application of formulas a secondary aim.
Students must be able to identify different shapes before learning about the area of a shape. Start by teaching the student that each shape falls into a specific category. The Common Core State Standards Initiative recommends that you teach students that shapes from different categories can share attributes but still belong to different categories. Inform students that triangles, rectangles and squares all belong to the large category of polygons. Third-graders should have the ability to recognize polygons in the subcategories that encompass both triangles and quadrilaterals.
Give students an example to demonstrate how rhombuses, rectangles and squares belong to the quadrilateral group because they each have four sides. Once students understand this, show them examples of objects that don't belong in the quadrilateral group. Finally, show them several shapes and ask them to identify each shape as a quadrilateral or non-quadrilateral. Once students master one category, move on to the next category and teach them about triangles. Show third graders examples of pentagons, hexagons and other shapes with the intent of helping them identify shapes and classifying them into subcategories of polygons such as triangles, quadrilaterals, pentagons, hexagons and other categories.
Have your students to draw examples of the various types of quadrilaterals. You can divide students into teams that require each student to come up to the board and draw a quadrilateral selected by the teacher. Keep score to turn the lesson into a game. In addition to drawing figures, ask students to identify polygons that don't belong in the category of quadrilaterals. If a student gets the answer wrong, show her an example of a the correct answer and ask her to attempt to figure out what kind of polygon her incorrect choice is.
Breaking Down Shapes
Teach students the formula to find the area of simple shapes. For example, ask students to find the area of a square by squaring the length of one side, or the area of a rectangle by multiplying the length of the width by the height. Explain that by breaking more complicated shapes into simpler shapes, you can calculate the area of each shape independently and then add the two answers together. For example, if the student can break a quadrilateral shape into two smaller quadrilaterals, then he can calculate the area of both shapes independently and add both values together to arrive at the total area.
Show the students two rectangles of different sizes. Ask students to visually identify the bigger rectangle. Then show two rectangles that have the same area, but have differing widths and heights. Ask them to identify the rectangle with the larger area. Explain that both rectangles actually have the same area and to figure this out you need to measure the sides and multiply the length times the width. Give students a sheet of paper with various shapes and a ruler. Have students measure each side and identify the length in inches for each side, then help students use the values to calculate area.
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