the answers should be

a$)2\mathrm{.}78$

b$)$ d$1=0\mathrm{.}800$ in

d$2=1\mathrm{.}131$in

d$3=0\mathrm{.}566$in

d$4=0\mathrm{.}669$in

d$5=0\mathrm{.}800$in