According to the Jenss model for predicting the height of preschool children, the rate of growth of a typical preschool child is
$$R(t)=1.0490 t^{4}-4.2255 t^{3}+12.7659 t^{2}-25.7119 t+32.28 \quad\left(\frac{1}{4} \leq t \leq 1\right)$$
cm/year, where $t$ is measured in years. The height of a typical 3-month-old preschool child is $60.30 \mathrm{cm}$
a. What is the height of a typical infant at age $t ?$
b. Use the result of part (a) to estimate the height of a typical 1-year-old child.