To develop strategies to determine the formula of 2-D shapes (triangle and quadrilaterals)
Learning description:
- To identify the properties of each 2D shapes (triangles and quadrilaterals)
- To develop relationship among shapes given
- To determine the area of triangle and quadrilaterals by converting the shapes to the rectangle
- To use the formula of rectangle to determine the area of triangles and quadrilaterals
Have you ever wondered why the formula of triangle area is 1/2 x b xh? Have you ever thought that actually it is connected with the area of rectangle?
When you have a triangle and created a duplicate of it, you actually can convert the triangle to rectangle. As we all know, to find the area of rectangle is by multiplying the length and the width, while triangle is actually half of rectangle. Therefore, the formula became 1/2 of base times height. In this case the base and height in triangle represent lenght and width in rectangle. You can find other formula of 2D shapes area by connecting the shapes with rectangle. Try to convert, parrarellogram, trapezoid, kites, and rhombus. Soon you will be able to answer the question: Why the formula of trapezoid area is 1/2 x (b1+b2) x h?
Have a look at the students work below. Here the teachers asked the students to make a visual presentation about the formula of the area of triangle and quadrilaterals (parallelogram, rhombus, kite, isosceles trapezoid, and right angle trapezoid).