Evaluate
Plan the calculation so rounding cannot accumulate. Three of the four factors are non-terminating decimals (, , ). If each is rounded to four or five digits before multiplying, the small errors multiply too. The safe plan is to keep everything as exact fractions and round only the final number.
Turn every factor into an exact fraction. Writing ,
These are the reduced forms; and are prime, so nothing further cancels against them.
Multiply the fractions in one go.
Divide once, at the end.
Only this single division introduces any rounding, so the four significant figures shown are all trustworthy.
Compare with the rounded route to see the damage. Using , then and , the rounded chain gives — about too large, a relative error of roughly that comes entirely from truncating and too early. Small as that is, it already corrupts the sixth significant figure and shifts the two-decimal answer. The correct value is .
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