Which of the following are exact numbers?
a. There are $100 \mathrm{~cm}$ in $1 \mathrm{~m}$.
b. One meter equals $1.094$ yards.
c. We can use the equation
${ }^{\circ} \mathrm{F}=\frac{9 \circ}{2} \mathrm{C}+32$
to convert from Celsius to Fahrenheit temperature. Are the numbers $\frac{9}{3}$ and 32 exact or inexact?
d. $\pi=3.1415927$.