Notes
Measuring Space in Two Dimensions (12.1-12.5)
Part I
Next to figure 1 write the appropriate area formula.
Next to figure 2 draw one of the two congruent shapes, then write an area formula for this shape based
on the area formula you wrote for figure 1 (use the same abbreviations).
Next to figure 3 show that the two smaller triangles equal the area of the large triangle, then write a
formula for the area of the large triangle based on the area formula you wrote for figure 1.
Next to figure 4 draw a non-rectangular parallelogram using the two pieces in figure 4, then write an
area formula for the parallelogram based on the area formula you wrote for figure 1.
Next to figure 5 draw one of the congruent shapes, then write an area formula for this shape based on
the area formula you wrote for figure 1.
1
2
3
4
5
Page 1 of 4
Notes
Part II
Use dissections to create rectangles from the given parallelograms. Use duplications to create
rectangles or parallelograms from the given triangles and trapezoids. What is the area of each original
figure on both pages? The distance between two pegs is counted as 1 unit, so count segments, not
pegs!
1
2
3
4
Area of figure 1= ________________ units
Area of figure 2= ________________ units
Area of figure 3= ________________ units
Area of figure 4= ________________ units
Page 2 of 4
Notes
5
6
7
8
Area of figure 5= ________________ units
Area of figure 6= ________________ units
Area of figure 7= ________________ units
Area of figure 8= ________________ units
Page 3 of 4
Notes
Part III
Find the area of the following shapes by using area formulas, dissection it into shapes you know the area
formula for, or creating a rectangle around the shape and subtracting the extra areas. The distance
between two pegs is counted as 1 unit, so count segments, not pegs!
A
B
Area=
D
Area=
Area=
Area=
F
E
Area=
G
C
Area=
H
Area=
I
Area=
Area=
Find the perimeter of figure A, c, and I.
Page 4 of 4