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Math Common Core Standard: 7.G.6 7th Grade Math
Area of a Triangle Formula equals one half base times height ( 1/2 b*h )
The area of a triangle is found by taking the length of the base and the height and plugging the appropriate numbers in the area of a triangle formula. Any leg of the triangle can be the base, and the height is measured from the vertex opposite the base and is perpendicular to the base.
How do we find the area of a triangle?
In the following example problems the altitude is given. If the altitude of the triangle is not known you can use Heron's formula to find the area.
How is area of the triangle different than the perimeter of the triangle?
The perimeter is the distance around the triangle and the area is measure of the space covering the triangle.
The formula for the perimeter of the triangle equals:
Find the perimeter of a triangle with sides of 7,9, and 11 units.
Solution: 7+9+11 = 27 units
Perimeter = a+b+c in which a, b ,and c are the sides of the triangle
3
X
Z
Y
Example problem 3 Triangle wxy has an area of how many units?
Example problem 2 Triangle xyz has an area of how many units?
Area=1/2 Base x Height
Step 1. 1/2 *( 4*3) Use 4 as your base therefore the altitude will be 3 units. Notice it is perpendicular to the base.
Step 2. 1/2 *12
Step 3. 6 unit^2 = Triangle ABC Area
4
C
B
A
Example problem 1
Find the area of triangle ABC
Area of a Triangle-7th Grade Math
In this example the altitude is given so the leg opposite the vertex is your base. (5) Notice the dotted line is perpendicular to the base
Area= 1/2 Base x Height
Step 1. 1/2 *( 5*8)
Step 2. 1/2 *40
Step 3. 20 unit^2 = Area
In this example the altitude is given so the leg opposite the vertex is your base. (6) Notice the dotted line of your altitude is perpendicular to the base
Area = 1/2 Base x Height
Step 1. 1/2 *( 6*5)
Step 2. 1/2 *30
Step 3. 15 unit^2 = Area
5
8