1. Geometry 11 Jan 2013 Warm up: Check your homework. For EACH PROBLEM: √ if correct. X if incorrect. Work with your group mates to find and correct any errors. Please use a different color. Use the HW rubric on the purple sheet and grade yourself. I will revise if necessary!

2. Homework Expectations Start by writing the given information show any sketches; write down the problem What do you KNOW? Clearly write what you are trying to find SHOW ALL WORK clear and concise; EASY for someone else to follow Area/ volume: 1) formula 2) substitute 3) calculate 4) units Underline or box your ANSWER. VALID attempt for all problems. √ or X – check all problems and make corrections

3. Objective Students will derive formulas for area of trapezoids and kites. Students will take notes, participate in a whole class investigation using think-pair-share. Homework Due TODAY pg. 425: 1 - 15 odds, 17, 18, 20, 21 (use graph paper) For all area problems, use the following format: 1)Write the formula 2)Substitute values 3)Do the calculation/ check 4)Add UNITS QUESTIONS????

4. Homework due Tuesday 1) 8.2, pg. 430 +: 1 – 15 odds, 19, 20, 22, 29 2) Study and KNOW the area formulas for rectangles, parallelograms, triangles, trapezoid and kites 3) CHOOSE two of the 5 shapes listed above AND explain HOW WE DERIVED THE FORMULAS (you may use a sketch to help!)

5. Copyright Tim Morris/St Stephen's School What is the area of this parallelogram? PARALLELOGRAM MOVE TO HERE! b = base h=height A = bh

6. To find the area of a triangle: The height = the perpendicular distance from the opposite vertex to the base The area of this rectangle is base x height The area of the triangle is ½ the area of the rectangle h b Area of triangle = ½ bh

7. Add to Chapter 8 Area Formulas Graphic Organizer ShapeArea FormulaDefinition of Variables RectangleA = bhb = base (any side) h = height (perpendicular to base) Parallelogram A = bh (same as above) TriangleA = ½ bh b = base (any side) h = height (altitude from base)

8. 8.2 investigations review– altitude– PERPENDICULAR distance from vertex to opposite side or between bases pg. 429- 430 Finish investigations for finding area of a trapezoid and a kite

9. Term Definition Example Triangle area conjecture The area of a triangle is given by the formula, A is the area, b is the base, and h is the height of the triangle Trapezoid Area Conjecture The area of a Trapezoid is given by the formula, A is the area, b 1 and b 2 are the bases and h is the height of the trapezoid Kite Area Conjecture The area of a Kite is given by the formula, A is the area, d 1 and d 2 are the lengths of the diagonals

10. debrief how can you relate each shape to a rectangle? how did you find the formula for area of a triangle? trapezoid? kite? what will you do to help yourself remember the formulas?