Precision Error?

[WhatMeWorry` via Digitalmars-d-learn]

    float computeToFitInWindow(uint rows, uint cols)
    {
        // code removed ...
        writeln(hexWidth);
        return hexWidth;
    }

    unittest
    {
        assert(computeToFitInWindow(1, 1) == 2.0f, "This assert 
failed");
        assert(computeToFitInWindow(3, 3) == 0.8f, "This assert 
failed");
        assert(computeToFitInWindow(2, 2) == 1.14286f, "This 
assert failed");   // Line 74
    }


2
0.8
1.14286
main.d(74): [unittest] This assert failed

Can someone tell me why line 74 fails?   Aren't they both 
1.14286?  I presume it has to do with precision.  Is there a 
technique to address this issue.