Consider the following spot interest rates for maturities of one, two, three, and four years.

$r_1=4\mathrm{.}5\%,r_2=4\mathrm{.}9\%,r_3=5\mathrm{.}6\%,r_4=6\mathrm{.}4\%$

What are the following forward rates, where $f_{1,k}$ refers to a forward rate for the period beginning in one year and extending for $k$ years?