moomoomath logo header
lime green horizontal line
Welcome to MooMooMath
Quick Math Homework Help
Geometry Coach
geometry coach lesson plans
isosceles triangle
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



5
white box triangle area

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

black line for area triangle page
black line for area triangle page
black line
black line
black line
black line
black line

How to find the area of a triangle

You may also enjoy
Area formulas for plane shapes

Perimeter formulas for plane shapes

Related Sites...

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           

Finding the area of a triangle 6 ways

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

acute triangle
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 

triangle/use heron's formula
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

8