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Finding the Fourth Proportional to 485.10, 668.61 and 391.50

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Solution

The fourth proportional to 485.10, 668.61 and 391.50 is: 539.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.10 : 668.61 = 391.50 : x
  2. Step 2: Convert to fraction form
    485.10/668.61 = 391.50/x
  3. Step 3: Cross multiply
    485.10x = 668.61 × 391.50
  4. Step 4: Simplify right side
    485.10x = 261,760.82
  5. Step 5: Solve for x
    x = 261,760.82/485.10
  6. Step 6: Final answer
    x = 539.60

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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.