The main line of this problem should be pretty straightforward. The other lines, however, get quite complicated and do not necessarily represent best play. Have fun. =)
(;AW[qb]AW[pb]AB[ob]AB[nc]AB[nd]AB[mb]AW[lc]AW[mc]AW[jc]AB[me]AB[lf]AB[kf]AW[mf]AW[ne]AW[oe]AW[od]AW[oc]AB[pc]AB[pd]AB[pe]AB[ph]AW[jh]AW[lh]AW[ih]AB[ig]AB[hg]TR[ne]TR[oe]TR[od]TR[oc]C[Black to capture the triangle stones. Don't worry about the status of the other white stones. Just focus on technique.]AP[goproblems]
(;B[of];W[nf]
(;B[ng];W[mg]C[White escapes!])
(;B[mg];W[ng]
(;B[og];W[nh])
(;B[nh];W[og]
(;B[pf];W[md])
(;B[oh];W[pg];B[qg];W[pf];B[qf]C[RIGHT])
(;B[pg];W[pf];B[oh]C[RIGHT])))
(;B[mh];W[md]))
(;B[nf];W[of]
(;B[ng];W[md])
(;B[pf];W[ng]
(;B[mg];W[md])
(;B[og];W[nf]
(;B[nh];W[mg])
(;B[mh];W[md])
(;B[mg];W[nh]))
(;B[nh]))
(;B[og];W[ng];B[pf];W[nf]
(;B[mh];W[md])
(;B[nh];W[mg])
(;B[mg];W[nh]))
(;B[mg];W[md];B[nb];W[ng]
(;B[nh];W[mf];B[le];W[pg]
(;B[nf];W[pf])
(;B[oh];W[pf])
(;B[mh];W[pf])
(;B[lg];W[pf])
(;B[qg];W[mh]
(;B[lg];W[oh])
(;B[nf]MA[mf]C[Ko is not best.]))
(;B[pf];W[mh]
(;B[lg];W[oh])
(;B[nf]MA[mf]C[Ko is not best.])))
(;B[mf]
(;W[og]
(;B[ni];W[lb])
(;B[mh];W[lb])
(;B[nh];W[oh];B[oi];W[ni];B[mh];W[pi];B[oj]
(;W[pg]C[CHOICE];B[qh];W[qg]
(;B[qf];W[rh];B[qi];W[ri];B[qj];W[rf]
(;B[rg];W[sg];B[pf];W[rg]
(;B[qc];W[rc])
(;B[re];W[qd]))
(;B[qc];W[rb];B[rc];W[lb])
(;B[rb];W[qc];B[rc];W[qd]))
(;B[re];W[rh];B[qi];W[ri];B[qj];W[rf]C[CHOICE]
(;B[qc];W[rb];B[rc];W[lb])
(;B[rb]
(;W[qc]C[NOTTHIS];B[rc])
(;W[rc];B[qc];W[ra];B[sb];W[sc];B[pa];W[sa];B[rb];W[sb];B[oa];W[se]))))
(;W[pf])))
(;W[pg]
(;B[nh];W[pf])
(;B[pf];W[og]
(;B[nh];W[qg])
(;B[qg];W[oi]))
(;B[oh];W[pf])
(;B[qg];W[nh])))))
(;B[pf];W[md])
(;B[mg];W[md])
(;B[ng];W[md])
(;B[md];W[mg]
(;B[nf];W[of];B[ng];W[og];B[nh];W[oh]
(;B[oi];W[ni])
(;B[ni];W[oi]))
(;B[mh];W[ng];B[lg];W[nh];B[mi];W[ni])))