12.56 because you multiply the radius by 2 then multiply that by 3.14
Answer:
Use Less Heat and Air Conditioning. ...
Replace Your Light Bulbs. ...
Drive Less and Drive Smart. ...
Buy Energy-Efficient Products. ...
Use Less Hot Water. ...
Use the "Off" Switch. ...
Plant a Tree.
Answer:
It is accepted by a few scientists.
Answer btw I am new can be friend