Sunday, May 19, 2013

How to find the perimeter of a parallelogram

 

Perimeter of a Parallelogram

Watch the video to see each problem worked out

Perimeter of a Parallelogram

In order to find the perimeter of a parallelogram you can use two methods.

Method 1 Perimeter of parallelogram equals, add all four sides

 

Method 2 Perimeter of parallelogram equals 2 l +2w l = length w = width

 

Problem 1 Find the perimeter of a parallelogram with a side of 3 units and 10 units.

 

perimeter of parallelogram

 

 

Step 1. The opposite sides of a parallelogram are congruent. Therefore, if you know the length of one side you know the length of the other.

 

Step 2. Add all four sides 3+3+10+10=26 units or (2*3) + (2*10) = 6+20=26 units

 

Problem 2 Find the perimeter of a parallelogram with a side of 8 units and a height of 6 units and an angle measure of 60 degrees.

 

perimeter of a parallelogram

 

 

Step 1 Use the altitude to find the length of the missing side. 

 

Step 2 The altitude creates a 30-60-90 triangle. If you find the hypothesis of the 30-60-90 Triangle this will be the length of the missing side.

 

Step 3 The height becomes the long leg which equals x√(3 ) x = the length of the short leg

  

Since you know the length of the long leg you can use 6=x√3 

  

Step 3A 6/√3 = √3/√3  

  

Step 3B (6√3)/2 =2√3  

 

Step 4 Now that I know x I can use 2x to find the hypotenuse

  2*2√(3 ) =4√3  

 

Step 5. Now use the perimeter formula for a parallelogram 2l + 2w

   

2*8 + 2*4√3

  

16 + 8√3 this is your final answer because you can add a constant and a radical