Name _______________________________________ Date __________________ Class __________________
LESSON
8-3
Area of Triangles and Trapezoids
NOTES
The diagram shows how you can cut a parallelogram into two
congruent triangles.
Remember that
the formula for
the area of a
parallelogram is
A  b • h.
1
the area of the parallelogram.
2
1
The formula for the area of a triangle is A 
• b • h.
2
The base of a triangle can be any side. The height of a triangle is the perpendicular
distance from the base to the opposite vertex.
The area of the triangle is
Find the area of each triangle.
1.
2.
_______________________
3.
________________________
________________________
4. What is the area of a triangle with base 16 m and height 10 m?
__________________
5. What is the area of a triangle with base 25 mm and height 50 mm?
__________________
Name _______________________________________ Date __________________ Class __________________
LESSON
8-3
Area of Triangles and Trapezoids
NOTES (continued)
In a trapezoid, the parallel sides are called the bases. One base is
always longer than the other. The bases are labeled base 1 and
base 2. The height of a trapezoid is the perpendicular distance between the bases.
Area of trapezoid 
1
h(b1  b2)
2
Find the area of each trapezoid.
6.
7.
_______________________
8.
________________________
________________________