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Finding the Fourth Proportional to 682.08, 939.90 and 485.40

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Solution

The fourth proportional to 682.08, 939.90 and 485.40 is: 668.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    682.08 : 939.90 = 485.40 : x
  2. Step 2: Convert to fraction form
    682.08/939.90 = 485.40/x
  3. Step 3: Cross multiply
    682.08x = 939.90 × 485.40
  4. Step 4: Simplify right side
    682.08x = 456,227.46
  5. Step 5: Solve for x
    x = 456,227.46/682.08
  6. Step 6: Final answer
    x = 668.88

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.