Note that
10² = 100
0.08² = 0.0064
and
101.6064 = 100 + 1.6 + 0.0064
It also happens that
1.6 = 2 • 10 • 0.08
which means
101.6064 = 100 + 1.6 + 0.0064
101.6064 = 10² + 2 • 10 • 0.08 + 0.08²
101.6064 = (10 + 0.08)²
101.6064 = 10.08²
which means
√101.6064 = 10.08
which, to one decimal place, is approximately 10.1.