Announcements Finish factoring expressions Study for quiz over: Writing addition and subtraction expressions Writing and expanding multiplication expressions Factoring expressions (will finish on Tuesday, then take quiz) Complete this entire lesson (notes and exercises) When finished: Holt book p #6-18 and 20-22

No Warm Up PUT THIS ENTIRE POWERPOINT IN SLIDE SHOW FORM

Opening Exercise Name each shape Word bank: quadrilateral, parallelogram, rectangle, square, trapezoid, acute triangle, right triangle, obtuse triangle

Opening Exercise Name each shape Word bank: quadrilateral, parallelogram, rectangle, square, trapezoid, acute triangle, right triangle, obtuse triangle

Lesson 1 - Area of Parallelograms Discussion Based on the image, create a definition for each shape

Lesson 1 - Area of Parallelograms Discussion Based on the image, create a definition for each shape

Quadrilaterals are any 4 sided figure. Today you are going to find the area of one of these quadrilaterals: the parallelogram. What does area mean? Area is the number of square units that make up the inside of the shape How do you find the area of a rectangle? Multiply the base by the height (or length by width) Lesson 1 - Area of Parallelograms Discussion

Draw this parallelogram neatly in your notes: Since we know how to find the area of a rectangle, how can we change the parallelogram into a rectangle? Lesson 1 - Area of Parallelograms Discussion

Q: Since we know how to find the area of a rectangle, how can we change the parallelogram into a rectangle? A: Cut off a triangle on one side of the parallelogram and glue it to the other side Draw a dotted perpendicular line to show the triangle you would cut. Lesson 1 - Area of Parallelograms Discussion

Could the dotted line be drawn in a different location? The base and height of a parallelogram form a right angle (90˚) Lesson 1 - Area of Parallelograms Discussion height base

If we move the triangle to the other side we create what shape? A rectangle Lesson 1 - Area of Parallelograms Discussion

How does this compare to the base and height of the parallelogram? They are the same When we moved the triangle, did the area inside the shape change? The area did not change because it is the same size. It just looks different. Lesson 1 - Area of Parallelograms Discussion

Find the area of the rectangle. Lesson 1 - Area of Parallelograms Discussion

If the area of the rectangle is 21 square inches, (or 21 inches squared or 21 in²) what is the area of the original parallelogram? Why? The area of the original parallelogram is also 21 in² because both shapes have the same amount of space inside. Lesson 1 - Area of Parallelograms Discussion

The formula to calculate the area of a parallelogram would be the same as a rectangle, A = bh, where b = measurement of base and h = measurement of height Lesson 1 - Area of Parallelograms Discussion

Why is the height the vertical line and not the slanted edge? If you look back at the rectangle we created from the parallelogram, the base and height of both the rectangle and the original parallelogram are perpendicular (lines make 90˚ angles) to each other. Therefore, the height of a parallelogram is the perpendicular line drawn from the top base to the bottom base. Lesson 1 - Area of Parallelograms Discussion

Exercises 1

Homework