Question 979185: Please help Which of the following are always,sometimes or never true. Examples to show would be very helpful:
If you double the radius of a circle the area doubles ?
If you double the radius the circumference doubles?
If you double the edges of a cuboid the volume doubles?
If you double the edges the surface area doubles?
If you double the sides of a rectangle the area doubles?
Answer by anand429(138)   (Show Source):
You can put this solution on YOUR website! Area of a circle =  =A (say)
so,if radius is doubled,
New Area = 
= =4A
Hence area becomes 4 times and not double,
So 1st statement is wrong.
Circumference =  =C (say)
so, if radius is doubled,
New circumference =  =2C
Hence, circumference is doubled,
Statement 2 is true for all cases.
Volume of cuboid(with sides a,b,c) = a*b*c = V (say)
If edges are doubled,
New volume = 2a*2b*2c =8abc = 8V
Hence, Statement 3 is wrong.
Similarly, follow for others.
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