Root Locus Problem

Root Locus Problem
Problem RLocus11

In this problem, the system has three poles:

G(s) = .5/[s(s + 1)(s + 2)]

The system is in a feedback loop as shown below.

It is desired that the closed loop system dominant poles (Every other pole is at least 5 or 10 times as far into the LHP so that any response from those poles dies out so quickly that the system looks second order - the dominant pole(s)) have a damping ratio of 0.7.

Determine the gain that produces poles with the required damping ratio.
Determine if those poles are - in fact - dominant, i.e. the third pole is at least 5x as far into the LHP.