An aluminium wire is used to form a rectangle of side length 
and width 
at 20 °C. The rectangle is then heated to 70 °C. Calculate the ratio of the:
diagonals
perimeters
areas
of the rectangle at the initial temperature (20 °C ) to that at the final temperature (70 °C), correct to 4 decimal places.
The linear expansivity of aluminium is 
.
