Area of a Parallelogram Lesson 4.3 January 30th, 2012 Area of a Parallelogram

A little joke...

Pop Quiz!! Take out a sheet of paper and put number 1 – 10 on the sheet of paper. There will be a different question on each slide. Once the slide changes, I will not go back to it.

Question #1 What is the formula to find diameter?

Question #2 What is the formula to find radius?

Question #3 What is the radius of this circle? 14 cm

Question #4 What is the diameter of this circle? 3.5 cm

Question #5 Which line segments represent the diameter, radius and center of this circle? R O S Q

Question #6 What is the definition for the circumference of a circle?

Question #7 What is one of the two formulas for finding the circumference of a circle?

Question #8 What is Л?

Question #9 Find the circumference of a circle with a diameter of 10 cm.

Question #10 Find the circumference of a circle with a radius of 4 cm.

Bonus Question What is the relationship between radius and diameter?

d/2

2r

d/2 14/2

D = 2r D = 2 x 3.5 D = 7

0 = Center S – Q = Diameter R - O, S – O and Q – O = Radii

The circumference is the distance around the circle The circumference is the distance around the circle. Also known as perimeter.

C = 2Лr Or C = Лd

Л is a number that never repeats, never ends and can never be written as a fraction. The value of Л is approximately 3.14.

C = Лd C = 3.14 x 10 C = 31.4 cm.

C = 2Лr C = 2 x 3.14 x 4 C = 6.28 x 4 C = 25.12 cm

Diameter is twice as much as radius OR Radius is half of diameter.

Go to the Practice Section of Your Binder... Solve the questions on page 138 in your textbook. Questions #3, 4, 5, 6, 7, and 9. You have 20 minutes to complete this assignment and hand it in.

Back to the Parallelogram What is a parallelogram? It is like a rectangle that is tilted.

Any side of a parallelogram is called its base. The height is the length of a line segment that joins parallel sides and is perpendicular to the base. height base

Both a rectangle and a square can be a parallelogram. Any parallelogram can be cut and rearranged to form a rectangle.

But HOW!! A = b x h A = 7 x 5 A = 35 cm A = b x h A = 2.5 x 7.5 The height can be drawn outside the parallelogram A = b x h A = 7 x 5 A = 35 cm 7 cm 5 cm 7.5 m A = b x h A = 2.5 x 7.5 A = 18.75 m

The parallelogram and the rectangle have the same area. So, Area of Parallelogram = b x h Area of Rectangle = b x h

Solve this: 6 cm 3 cm A = b x h A = 6 x 3 A = 18 cm

Find the area: A = b x h A = 10 x 6 A = 60 m 6 m 10 m

I have a garden and a patio. It is pictured below I have a garden and a patio. It is pictured below. Yes, please draw this... 6 m 5 m 10 m 6

A) what is the area of the patio? A = b x h A = 10 x 5 A = 50 m Therefore the area of the patio is 50 m

What is the area of the patio and the gardens? A = b x h A = 16 x 5 A = 80 m Therefore, the gardens and patio are 80 m

How could you find the area of the gardens only. 80 – 50 = 30 m Both gardens are 30 m One garden is 15 m

Homework... Textbook page 142 # 6, 8, 9, 10 Workbook 4.3 Worksheets