The document provides instructions and questions for a math worksheet on formulas for calculating the areas of different shapes. Students are asked to write down area formulas they know for triangles, rectangles, parallelograms, squares, circles, and trapezoids. They are then prompted to explain why the area formulas for rectangles, triangles, and parallelograms are what they are. Finally, students are instructed to come up with explanations supported by pictures for why the area formulas for trapezoids, rhombuses, and kites are what they are.

1. Opener:
Please complete the following on your opener sheet.
Think about the formulas you know to find the areas of
shapes. Write down as many as you can think of.
Triangle - Rhombus -
Rectangle - Kite -
Parallelogram - Circle -
Square - Trapezoid -
Title: Mar 12­8:17 AM (1 of 5)

2. Section 9.1: Developing Formulas for Triangles & Quadrilaterals
Why is the area of a rectangle equal to the base*height?
Title: Mar 12­8:22 AM (2 of 5)

3. Why is the area of a triangle equal to the (1/2)base*height ?
Title: Mar 12­8:28 AM (3 of 5)

4. Why is the area of a parallelogram equal to the base*height?
Title: Mar 12­8:38 AM (4 of 5)

5. Your Turn! Come up with as many arguments, supported by pictures, to
explain the answers to the following questions as you can. Use the shapes I
handed out. You should cut them out and see what you can come up with.
When you come up with a possible explanation, glue it to the blank paper
provided. If you need a hint, raise your hand.
1. Why is the area of a trapezoid equal to the (base1 + base2)*height?
2
2. Why is the area of a rhombus and a kite equal to (1/2)diagonal1*diagonal2?
Title: Mar 12­8:42 AM (5 of 5)