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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.