Lesson 9 : Tape measurmenets 2

Units of length :

1) Metric system 

• Adopted as international system .
• The meter is the length of the path traveled by light in vacuum during a time interval of 1/299792458 of a second .

2) Imperial ( English ) system : 

• foot .
• the popular belief is that original standard was the length of a man's foot .
• the foot used today is the imperial foot , which is defined to be exactly 0.3048 meters .

Units of Area :

1) Imperial ( English ) system ; 

• square foot , yard and inch 
• 1 Acre = 43560 square feet 

2) Metric 

• square meter , kilometer , decimeter , centimeter and millimeter .
• 1 hectare = 10000square meters