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Find the area of an Isosceles triangle with a height of 8 units and a base of 5 units.
Area =1/2 • (5 units) • (8 units)
Area =1/2 • (40 units^2)
Area = 20 units^2
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Triangle is Isosceles
X and Y cordinates of the Vertices
Triangle is Equilateral
Two sides and included angle
Altitude of Triangle is unknown
Base of Triangle and Altitude
How to find the area of a triangle
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The area of a triangle This page provides step by step directions and many sample problems of finding the area of a triangle
Area of a Triangle/Math Expression This is a very helpful page. Neat,easy to follow, and includes videos,sample problems, and pictures for finding the area of a triangle.
1/2 Base * Height
Practice Problems Box Method
Practice Problems Side angle Side
Equilateral triangle Area
Box Method
Side Angle Side ( SAS)
Heron's Formula
6 Formulas for finding the area of a triangle
How do you find the area of a triangle? There are several methods for finding the area of a triangle. The most commonly used equation for the area of a triangle that works for all triangles is one half base times height.
1/2 b*h
b = base
h = height
Below are videos that show an example of each different method.
->The left hand column is the needed information.
->The video shows an example problem explaining how to find the area of a triangle with the given information.
Choose the video from the handy chart that best helps you find the area of the triangle based on the information you are given.
If you know ...
Use the following Method
Half Base times Height
An acute triangle has a height of 5 units and a base of 10 units. What is the area of this triangle?
Solution:
Area = ½ (10) *(5)A = ½ (50)A = 25 units^2 Remember area is always units squared
Find the area of a triangle with sides of 5 units,6 units, and 7 units.
With this example you can use Heron’s formula.
Solution:
Find S 5+6+7/2 = 18/2 = 9
Area = √(9(9-5))9-6)(9-7))
√(216 )=14.6868 units^2
Find the area of an equilateral triangle with of 4 units.
Solution: Area = 4^2√3/4
A =16√3/4
A =16 * 1.73/4
A =27.71/4 = 6.92 units^2
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