1. Geometry Drill 4/8/13
 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.

2. April is Math Month

3. Geometry
Find the distance

between points
A(1,4) and B(-3,9)

4. Objective
 SW recall area and
perimeter formulas so
that they can find the
area and perimeter of
irregular regions.

5. Compare:
 Regular polygons vs.
polygons

6. Perimeter of a
Rectangle
P=2b+2h
h
b

7. Area of a Rectangle
 A=bh
h
b

8. Area of a Triangle
 A=(1/2)bh
h
b

9. Irregular Region
 A region(shape)
composed of many
smaller
regions(shapes)

10. Area of an Irregular
Region
 The sum of the areas
of all the non-
overlapping parts of
the region

11. Find the area of the
irregular region
2
3 4

12. Perimeter of an
Irregular Region
The distance

around the
region.

13. Find the Perimeter of
the region
2
3 4

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

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

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

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

18. Find the perimeter of
rectangle ABCD B
C
3 in.
5 in.
D 4 in. A

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

20. Parallelogram

21. Parallelogram

22. Parallelogram

23. Parallelogram

24. Parallelogram

25. Parallelogram

26. Rectangle

27. b2
h
b1
b2
h
b1

28. b2
h
b1
b2
h
b1

29. b2 b2
h h
b1
b1

30. b1
b2
h
h
b2
b1

31. b1 b2
h
b2 b1
Parallelogram

32. AREA OF A
PARALLELOGRAM
A = bh

33. Find the area:
7 5
8

34. Find the area:
2 4
5

35. AREA OF A
TRIANGLE
A = 1/2(bh)

36. Find the area:
6
5
10

37. Find the area:
15
9
12

38. AREA OF A
TRAPEZOID
A = h/2(b1+b2)
b1 and b2 are the
bases

39. Find the area:
12
5
8

40. ALTERNATE
FORMULA AREA
OF A TRAPEZOID
A = length of
median times the
height

41. Find the Area of
Trapezoid ABCD
10
12

42. ABCD is a rhombus with
diagonals d1 & d2
A B
D C

43. AREA OF A
RHOMBUS
A = 1/2(d1d2)
d1 and d2 are the
diagonals

44. Area of a
Rhombus
Find the area of a
rhombus if the lengths
of the diagonals are
12m and 10 m.