Geometry Drill 4/22/14 In your own words define

perimeter and area Make a list of any formula you

know that applies to perimeter or area of a geometric figure.

ObjectiveSW recall area and perimeter formulas so that they can find the area and perimeter of irregular regions.

Compare:Regular polygons vs. polygons

Perimeter of a Rectangle

P=2b+2hh

b

Area of a Rectangle

A=bhh

b

Area of a Triangle

A=(1/2)bhh

b

Irregular RegionA region(shape) composed of many smaller regions(shapes)

Area of an Irregular RegionThe sum of the areas of all the non-overlapping parts of the region

Find the area of the irregular region

43

2

Perimeter of an Irregular RegionThe distance around the region.

Find the Perimeter of the region

43

2

Conclusions 1) To find the area of an irregular region, find the areas of its smaller _____ and find their _____.

Conclusions 1) To find the area of an irregular region, find the areas of its smaller _____ and find their _____.partssum

Conclusions 2) To find the perimeter of an irregular region, find the ________ around the region.

Conclusions 2) To find the perimeter of an irregular region, find the ________ around the region.

distance

Find the perimeter of rectangle ABCD

A

BC

D

5 in.

3 in.

4 in.

EXPLORATIONWe know how to find the area of a rectangle. How can I form a rectangle from this parallelogram?

Parallelogram

Parallelogram

Parallelogram

Parallelogram

Parallelogram

Parallelogram

Rectangle

b2

b2

b1

b1

h

h

b2

b2

b1

b1

h

h

b2

b1

hb2

b1

h

b2

b1h b2

b1

h

b2

b1

h

Parallelogram

b1

b2

AREA OF A PARALLELOGRAM

A = bh

AREA OF A TRIANGLEA = 1/2(bh)

AREA OF A TRAPEZOIDA = h/2(b1+b2)

b1 and b2 are the bases

ALTERNATE FORMULA AREA OF A TRAPEZOIDA = length of median times the height

Find the Area of Trapezoid ABCD

12

10

ABCD is a rhombus with diagonals d1 & d2

D C

A B

AREA OF A RHOMBUSA = 1/2(d1d2)

d1 and d2 are the diagonals

Find the area:

10

56

Find the area:

5

42

Find the area:

5

12

8

Find the area:

12

915

Find the area:

8

57

Area of a RhombusFind the area of a rhombus if the lengths of the diagonals are 12m and 10 m.