Calculating linear expansion of windshield 60cm*150cm

[**Mariam**]

Homework Statement

An automobile windshield has the dimensions 60cm by 150 cm. What minimum tolerance is needed in mm to prevent the windshield from breaking if the temperature changes by 200F (the linear expansion coefficient of glass is 9*10^-6 C-1)

Homework Equations

deltaL=alpha*Li*deltaT
T(F)=1.8*T(C)+32

The Attempt at a Solution

First I changes the change in temperature from F to C which resulted in deltaT=110.3C
(one of my questions is what is an easy and direct way to convert "CHANGE in temp" from F-C. Because the way I solved it was by assuming the Tinitial was 0F and Tfinal was 200F and I converted each of these to C and then subtracted.)
Second I used the formula once for height and once for width
deltaL(width)=60*9*10^-6*110.3=0.06cm=0.6mm
deltaL(height)=150*9*10^-6*110.3=0.15cm=1.5 mm

Is this correct

 

[haruspex]

Homework Statement

An automobile windshield has the dimensions 60cm by 150 cm. What minimum tolerance is needed in mm to prevent the windshield from breaking if the temperature changes by 200F (the linear expansion coefficient of glass is 9*10^-6 C-1)

Homework Equations

deltaL=alpha*Li*deltaT
T(F)=1.8*T(C)+32

The Attempt at a Solution

First I changes the change in temperature from F to C which resulted in deltaT=110.3C
(one of my questions is what is an easy and direct way to convert "CHANGE in temp" from F-C. Because the way I solved it was by assuming the Tinitial was 0F and Tfinal was 200F and I converted each of these to C and then subtracted.)
Second I used the formula once for height and once for width
deltaL(width)=60*9*10^-6*110.3=0.06cm=0.6mm
deltaL(height)=150*9*10^-6*110.3=0.15cm=1.5 mm

Is this correct

Looks ok, but most windshields are wider than they are high.